diff --git a/Cargo.lock b/Cargo.lock
index 064b86b..c500dec 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -226,6 +226,23 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f079e83a288787bcd14a6aea84cee5c87a67c5a3e660c30f557a3d24761b3527"
+
+[[package]]
+name = "chacha20"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65c35e4b699c7e15ccbe7ee35c005e4fc0a278d22238a2857e6ce2dadeda1b06"
+dependencies = [
+ "cfg-if",
+ "cpufeatures 0.3.1",
+ "rand_core 0.10.1",
+]
+
 [[package]]
 name = "chrono"
 version = "0.4.45"
@@ -310,6 +327,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "cpufeatures"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ca28b0ae3115b884660db4118d803791fd6756b6e88f39c0f3f7859060d7566"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "crc"
 version = "3.4.0"
@@ -678,8 +704,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -689,8 +717,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "300e883d756b2e4ec94e02791f39b04b522276138852cfc41d9fb7e904106099"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "r-efi",
+ "rand_core 0.10.1",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -851,6 +882,23 @@ dependencies = [
  "pin-project-lite",
  "smallvec",
  "tokio",
+ "want",
+]
+
+[[package]]
+name = "hyper-rustls"
+version = "0.27.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dfa8e654703247911e29c23fbeaa261834bd9bb74efba2f9acddc37bfb127f53"
+dependencies = [
+ "http",
+ "hyper",
+ "hyper-util",
+ "rustls",
+ "tokio",
+ "tokio-rustls",
+ "tower-service",
+ "webpki-roots",
 ]
 
 [[package]]
@@ -859,13 +907,21 @@ version = "0.1.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96547c2556ec9d12fb1578c4eaf448b04993e7fb79cbaad930a656880a6bdfa0"
 dependencies = [
+ "base64",
  "bytes",
+ "futures-channel",
+ "futures-util",
  "http",
  "http-body",
  "hyper",
+ "ipnet",
+ "libc",
+ "percent-encoding",
  "pin-project-lite",
+ "socket2",
  "tokio",
  "tower-service",
+ "tracing",
 ]
 
 [[package]]
@@ -1013,6 +1069,12 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "ipnet"
+version = "2.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "791930b43c0d5973160d90a8f3894509f2b273430f5c5c73b668636d0287c5c0"
+
 [[package]]
 name = "itoa"
 version = "1.0.18"
@@ -1111,6 +1173,12 @@ version = "0.4.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0ceec5bc11778974d1bcb055b18002eba7f4b3518b6a0081b3af5f21666da9ad"
 
+[[package]]
+name = "lru-slab"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4050469837a6ff301cd14c1f8f24f88549e6d548f24f64e2148eb0f72cebc51f"
+
 [[package]]
 name = "matchers"
 version = "0.2.0"
@@ -1189,7 +1257,7 @@ dependencies = [
  "num-integer",
  "num-iter",
  "num-traits",
- "rand",
+ "rand 0.8.7",
  "smallvec",
  "zeroize",
 ]
@@ -1397,6 +1465,62 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "quinn"
+version = "0.11.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4051e23e9185c255a7e33ef59cdbca87a22d359052eecd22fc6b901fb37d9d11"
+dependencies = [
+ "bytes",
+ "cfg_aliases",
+ "pin-project-lite",
+ "quinn-proto",
+ "quinn-udp",
+ "rustc-hash",
+ "rustls",
+ "socket2",
+ "thiserror",
+ "tokio",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-proto"
+version = "0.11.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9746dbde176634f4f2f1faf2404e30a31b2bc1e9cafb5329c95d8177a18c9fc"
+dependencies = [
+ "bytes",
+ "getrandom 0.4.3",
+ "lru-slab",
+ "rand 0.10.3",
+ "rand_pcg",
+ "ring",
+ "rustc-hash",
+ "rustls",
+ "rustls-pki-types",
+ "slab",
+ "thiserror",
+ "tinyvec",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-udp"
+version = "0.5.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35a133f956daabe89a61a685c2649f13d82d5aa4bd5d12d1277e1072a21c0694"
+dependencies = [
+ "cfg_aliases",
+ "libc",
+ "once_cell",
+ "socket2",
+ "tracing",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.47"
@@ -1420,7 +1544,18 @@ checksum = "22f6172bdec972074665ed81ed53b71da00bfc44b65a753cfde883ec4c702a1a"
 dependencies = [
  "libc",
  "rand_chacha",
- "rand_core",
+ "rand_core 0.6.4",
+]
+
+[[package]]
+name = "rand"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65c9fb96cbc91e3478eaae79a69fcd3f1ae4ad052e471fe6732fff548984b4af"
+dependencies = [
+ "chacha20",
+ "getrandom 0.4.3",
+ "rand_core 0.10.1",
 ]
 
 [[package]]
@@ -1430,7 +1565,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
 dependencies = [
  "ppv-lite86",
- "rand_core",
+ "rand_core 0.6.4",
 ]
 
 [[package]]
@@ -1442,6 +1577,21 @@ dependencies = [
  "getrandom 0.2.17",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63b8176103e19a2643978565ca18b50549f6101881c443590420e4dc998a3c69"
+
+[[package]]
+name = "rand_pcg"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "caa0f4137e1c0a72f4c651489402276c8e8e1cf081f3b0ba156d2cbeef09e86a"
+dependencies = [
+ "rand_core 0.10.1",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.18"
@@ -1497,6 +1647,58 @@ version = "0.8.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6f6ff9a378485b298a5286656da665ba74413d36db0979633275d2e708145d4"
 
+[[package]]
+name = "reqwest"
+version = "0.12.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eddd3ca559203180a307f12d114c268abf583f59b03cb906fd0b3ff8646c1147"
+dependencies = [
+ "base64",
+ "bytes",
+ "futures-core",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-rustls",
+ "hyper-util",
+ "js-sys",
+ "log",
+ "percent-encoding",
+ "pin-project-lite",
+ "quinn",
+ "rustls",
+ "rustls-pki-types",
+ "serde",
+ "serde_json",
+ "serde_urlencoded",
+ "sync_wrapper",
+ "tokio",
+ "tokio-rustls",
+ "tower",
+ "tower-http",
+ "tower-service",
+ "url",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "webpki-roots",
+]
+
+[[package]]
+name = "ring"
+version = "0.17.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4689e6c2294d81e88dc6261c768b63bc4fcdb852be6d1352498b114f61383b7"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "getrandom 0.2.17",
+ "libc",
+ "untrusted",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "ron"
 version = "0.12.2"
@@ -1524,7 +1726,7 @@ dependencies = [
  "num-traits",
  "pkcs1",
  "pkcs8",
- "rand_core",
+ "rand_core 0.6.4",
  "signature",
  "spki",
  "subtle",
@@ -1541,6 +1743,12 @@ dependencies = [
  "ordered-multimap",
 ]
 
+[[package]]
+name = "rustc-hash"
+version = "2.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b1e7f9a428571be2dc5bc0505c13fb6bf936822b894ec87abf8a08a4e51742d"
+
 [[package]]
 name = "rustix"
 version = "1.1.5"
@@ -1554,6 +1762,41 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "rustls"
+version = "0.23.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0d41d731c7d2f962d1ccc364cec258de3c0e93b38c2fb3ba97ac74513048d634"
+dependencies = [
+ "once_cell",
+ "ring",
+ "rustls-pki-types",
+ "rustls-webpki",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-pki-types"
+version = "1.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f4925028c7eb5d1fcdaf196971378ed9d2c1c4efc7dc5d011256f76c99c0a96"
+dependencies = [
+ "web-time",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-webpki"
+version = "0.103.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3c3cf1d8b1e7d4927e2d154c3fcb02979afb9939629c62cd9048d4f07b60ac2"
+dependencies = [
+ "ring",
+ "rustls-pki-types",
+ "untrusted",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.23"
@@ -1717,7 +1960,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a978451301f4db1d02937a4ab3ccce137717b81826e79b7d49ffe3244a13c3b8"
 dependencies = [
  "cfg-if",
- "cpufeatures",
+ "cpufeatures 0.2.17",
  "digest",
 ]
 
@@ -1728,7 +1971,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7507d819769d01a365ab707794a4084392c824f54a7a6a7862f8c3d0892b283"
 dependencies = [
  "cfg-if",
- "cpufeatures",
+ "cpufeatures 0.2.17",
  "digest",
 ]
 
@@ -1764,7 +2007,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77549399552de45a898a580c1b41d445bf730df867cc44e6c0233bbc4b8329de"
 dependencies = [
  "digest",
- "rand_core",
+ "rand_core 0.6.4",
 ]
 
 [[package]]
@@ -1927,7 +2170,7 @@ dependencies = [
  "memchr",
  "once_cell",
  "percent-encoding",
- "rand",
+ "rand 0.8.7",
  "rsa",
  "serde",
  "sha1",
@@ -1966,7 +2209,7 @@ dependencies = [
  "md-5",
  "memchr",
  "once_cell",
- "rand",
+ "rand 0.8.7",
  "serde",
  "serde_json",
  "sha2",
@@ -2035,6 +2278,7 @@ dependencies = [
  "axum",
  "chrono",
  "config",
+ "reqwest",
  "schemars",
  "serde",
  "serde_json",
@@ -2080,6 +2324,9 @@ name = "sync_wrapper"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
+dependencies = [
+ "futures-core",
+]
 
 [[package]]
 name = "synstructure"
@@ -2195,6 +2442,16 @@ dependencies = [
  "syn 3.0.3",
 ]
 
+[[package]]
+name = "tokio-rustls"
+version = "0.26.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c9cc2678c2cdd569ef8215e2afd7954ada2ae20b4fdd2c5fe6139a3b02d105db"
+dependencies = [
+ "rustls",
+ "tokio",
+]
+
 [[package]]
 name = "tokio-stream"
 version = "0.1.19"
@@ -2287,8 +2544,10 @@ dependencies = [
  "pin-project-lite",
  "tokio",
  "tokio-util",
+ "tower",
  "tower-layer",
  "tower-service",
+ "url",
 ]
 
 [[package]]
@@ -2365,6 +2624,12 @@ dependencies = [
  "tracing-log",
 ]
 
+[[package]]
+name = "try-lock"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
+
 [[package]]
 name = "typeid"
 version = "1.0.3"
@@ -2422,6 +2687,12 @@ version = "1.13.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6f5d3c3b1bf09027a88a6bc961fc00497d651009560b5463668dc81b0fa87a8"
 
+[[package]]
+name = "untrusted"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
+
 [[package]]
 name = "url"
 version = "2.5.8"
@@ -2458,6 +2729,15 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
+[[package]]
+name = "want"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa7760aed19e106de2c7c0b581b509f2f25d3dacaf737cb82ac61bc6d760b0e"
+dependencies = [
+ "try-lock",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
@@ -2483,6 +2763,16 @@ dependencies = [
  "wasm-bindgen-shared",
 ]
 
+[[package]]
+name = "wasm-bindgen-futures"
+version = "0.4.76"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c62df1340f32221cb9c54d6a27b030e3dba64361d4a95bed55f9aacb44da291d"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "wasm-bindgen-macro"
 version = "0.2.126"
@@ -2515,6 +2805,35 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "web-sys"
+version = "0.3.103"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8622dcb61c0bcc9fffa6938bed81210af2da9a7e4a1a834b2e37a59b6dfb6141"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "webpki-roots"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7dcd9d09a39985f5344844e66b0c530a33843579125f23e21e9f0f220850f22a"
+dependencies = [
+ "rustls-pki-types",
+]
+
 [[package]]
 name = "whoami"
 version = "1.6.1"
@@ -2590,7 +2909,16 @@ version = "0.48.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "677d2418bec65e3338edb076e806bc1ec15693c5d0104683f2efe857f61056a9"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.48.5",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets 0.52.6",
 ]
 
 [[package]]
@@ -2608,13 +2936,29 @@ version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a2fa6e2155d7247be68c096456083145c183cbbbc2764150dda45a87197940c"
 dependencies = [
- "windows_aarch64_gnullvm",
- "windows_aarch64_msvc",
- "windows_i686_gnu",
- "windows_i686_msvc",
- "windows_x86_64_gnu",
- "windows_x86_64_gnullvm",
- "windows_x86_64_msvc",
+ "windows_aarch64_gnullvm 0.48.5",
+ "windows_aarch64_msvc 0.48.5",
+ "windows_i686_gnu 0.48.5",
+ "windows_i686_msvc 0.48.5",
+ "windows_x86_64_gnu 0.48.5",
+ "windows_x86_64_gnullvm 0.48.5",
+ "windows_x86_64_msvc 0.48.5",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm 0.52.6",
+ "windows_aarch64_msvc 0.52.6",
+ "windows_i686_gnu 0.52.6",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc 0.52.6",
+ "windows_x86_64_gnu 0.52.6",
+ "windows_x86_64_gnullvm 0.52.6",
+ "windows_x86_64_msvc 0.52.6",
 ]
 
 [[package]]
@@ -2623,42 +2967,90 @@ version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b38e32f0abccf9987a4e3079dfb67dcd799fb61361e53e2882c3cbaf0d905d8"
 
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
 [[package]]
 name = "windows_aarch64_msvc"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc35310971f3b2dbbf3f0690a219f40e2d9afcf64f9ab7cc1be722937c26b4bc"
 
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
 [[package]]
 name = "windows_i686_gnu"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a75915e7def60c94dcef72200b9a8e58e5091744960da64ec734a6c6e9b3743e"
 
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
 [[package]]
 name = "windows_i686_msvc"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f55c233f70c4b27f66c523580f78f1004e8b5a8b659e05a4eb49d4166cca406"
 
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
 [[package]]
 name = "windows_x86_64_gnu"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "53d40abd2583d23e4718fddf1ebec84dbff8381c07cae67ff7768bbf19c6718e"
 
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
 [[package]]
 name = "windows_x86_64_gnullvm"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b7b52767868a23d5bab768e390dc5f5c55825b6d30b86c844ff2dc7414044cc"
 
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
 [[package]]
 name = "windows_x86_64_msvc"
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
 
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
 [[package]]
 name = "winnow"
 version = "1.0.4"
diff --git a/Cargo.toml b/Cargo.toml
index 89732ad..83f9fa8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,10 @@ axum = { version = "0.8.9", features = ["macros"] }
 chrono = { version = "0.4.45", features = ["serde"] }
 config = "0.15.23"
 schemars = { version = "0.9.0", features = ["chrono04"] }
+reqwest = { version = "0.12.28", default-features = false, features = [
+    "json",
+    "rustls-tls",
+] }
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.149"
 sqlx = { version = "0.8.6", features = [
diff --git a/README.md b/README.md
index 1b01aa6..e9e33cd 100644
--- a/README.md
+++ b/README.md
@@ -54,7 +54,8 @@ key, keep it up to date. Every value can also come from the environment
 │   ├── services/         implementations of the repositories (postgres/sqlx)
 │   └── utils/            configuration
 ├── LaTeX_pdf/            template of the lecture notes pdf (pandoc + pdflatex)
-├── storage/              files of the courses, stands in for the NAS (gitignored)
+├── storage/              files of the courses and associations, one folder each,
+│                         stands in for the NAS (gitignored)
 ├── db/
 │   ├── migrations/       dbmate migrations
 │   ├── schema.sql        dump regenerated by dbmate, do not edit by hand
diff --git a/config.example.yml b/config.example.yml
index b41c677..006f100 100644
--- a/config.example.yml
+++ b/config.example.yml
@@ -14,7 +14,8 @@ postgres:
 # Directory containing the built frontend (frontend/dist after `npm run build`)
 frontend_dir: frontend/dist
 
-# Where the files of the courses are stored (lecture notes and their pdf...).
+# Where the files of the courses and associations are stored (lecture notes and their
+# pdf...), one folder each: Cours/CS-477 Advanced OS/Notes/..., Associations/...
 # A local directory standing in for the NAS for now.
 storage_dir: storage
 
@@ -27,3 +28,12 @@ notes:
   # Shown in the header of the pdf, both optional
   student_name: Jane Doe
   student_id: "123456"
+
+# Optional: the focus sessions of the pomodoro are also counted in TimeTagger, tagged
+# with the course code, the tags and the name of the task. Without it, the time is only
+# counted in the app.
+# timetagger:
+#   # https://timetagger.app/api/v2 by default, or the api of your own server
+#   url: https://timetagger.app/api/v2
+#   # Api token, from the account page of TimeTagger
+#   token: ...
diff --git a/db/migrations/20260929180000_associations_focus.sql b/db/migrations/20260929180000_associations_focus.sql
new file mode 100644
index 0000000..4727d7e
--- /dev/null
+++ b/db/migrations/20260929180000_associations_focus.sql
@@ -0,0 +1,41 @@
+-- migrate:up
+
+-- Associations are managed like courses: same tasks, files and slots, without grades.
+ALTER TABLE courses ADD COLUMN kind TEXT NOT NULL DEFAULT 'course'
+    CHECK (kind IN ('course', 'association'));
+ALTER TABLE courses ALTER COLUMN kind DROP DEFAULT;
+
+-- Folder of the course in the storage (the NAS), relative to its root, named after the
+-- course: `Cours/CS-477 Advanced operating systems`. Moved when the course is renamed.
+-- The existing folders were named after the ids and are not moved by this migration.
+ALTER TABLE courses ADD COLUMN folder TEXT;
+UPDATE courses SET folder = 'Cours/' || trim(regexp_replace(
+    regexp_replace(COALESCE(code || ' ', '') || "name", '[/\\:*?"<>|]', '-', 'g'),
+    '\s+', ' ', 'g'));
+ALTER TABLE courses ALTER COLUMN folder SET NOT NULL;
+ALTER TABLE courses ADD CONSTRAINT courses_folder_key UNIQUE (folder);
+
+-- Path of a file in the folder of its course, without extension: `Notes/Lecture 1 Notes`
+-- (the note is `Notes/Lecture 1 Notes.md` and its pdf `Notes/Lecture 1 Notes.pdf`)
+ALTER TABLE course_files ADD COLUMN "path" TEXT;
+UPDATE course_files SET "path" = 'Notes/' || trim(regexp_replace(
+    regexp_replace("name", '[/\\:*?"<>|]', '-', 'g'), '\s+', ' ', 'g'));
+ALTER TABLE course_files ALTER COLUMN "path" SET NOT NULL;
+ALTER TABLE course_files ADD CONSTRAINT course_files_course_id_path_key UNIQUE (course_id, "path");
+
+-- Time spent working on a task, counted by the pomodoro
+ALTER TABLE tasks ADD COLUMN time_spent INTEGER NOT NULL DEFAULT 0 CHECK (time_spent >= 0);
+
+-- Kinds of the slots and tasks of the associations
+INSERT INTO tags ("name", color, scopes, slug) VALUES
+    ('{"fr": "Réunion", "en": "Meeting"}', '#db2777', '{slot,task}', 'meeting'),
+    ('{"fr": "Événement", "en": "Event"}', '#4f46e5', '{slot,task}', 'event');
+
+-- migrate:down
+DELETE FROM courses WHERE kind = 'association';
+DELETE FROM time_slots WHERE tag_id IN (SELECT id FROM tags WHERE slug IN ('meeting', 'event'));
+DELETE FROM tags WHERE slug IN ('meeting', 'event');
+ALTER TABLE tasks DROP COLUMN time_spent;
+ALTER TABLE course_files DROP COLUMN "path";
+ALTER TABLE courses DROP COLUMN folder;
+ALTER TABLE courses DROP COLUMN kind;
diff --git a/db/schema.sql b/db/schema.sql
index 19ce074..4a2d0fa 100644
--- a/db/schema.sql
+++ b/db/schema.sql
@@ -31,6 +31,7 @@ CREATE TABLE public.course_files (
     created_at timestamp with time zone DEFAULT now() CONSTRAINT lecture_notes_created_at_not_null NOT NULL,
     updated_at timestamp with time zone DEFAULT now() CONSTRAINT lecture_notes_updated_at_not_null NOT NULL,
     kind text NOT NULL,
+    path text NOT NULL,
     CONSTRAINT course_files_kind_check CHECK ((kind = ANY (ARRAY['note'::text, 'upload'::text])))
 );
 
@@ -64,7 +65,10 @@ CREATE TABLE public.courses (
     name text NOT NULL,
     code text,
     teachers text[] DEFAULT '{}'::text[] NOT NULL,
-    main_page_url text
+    main_page_url text,
+    kind text NOT NULL,
+    folder text NOT NULL,
+    CONSTRAINT courses_kind_check CHECK ((kind = ANY (ARRAY['course'::text, 'association'::text])))
 );
 
 
@@ -201,7 +205,9 @@ CREATE TABLE public.tasks (
     description text,
     links text[] DEFAULT '{}'::text[] NOT NULL,
     deadline timestamp with time zone,
-    done boolean DEFAULT false NOT NULL
+    done boolean DEFAULT false NOT NULL,
+    time_spent integer DEFAULT 0 NOT NULL,
+    CONSTRAINT tasks_time_spent_check CHECK ((time_spent >= 0))
 );
 
 
@@ -303,6 +309,14 @@ ALTER TABLE ONLY public.tasks ALTER COLUMN id SET DEFAULT nextval('public.tasks_
 ALTER TABLE ONLY public.time_slots ALTER COLUMN id SET DEFAULT nextval('public.time_slots_id_seq'::regclass);
 
 
+--
+-- Name: course_files course_files_course_id_path_key; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.course_files
+    ADD CONSTRAINT course_files_course_id_path_key UNIQUE (course_id, path);
+
+
 --
 -- Name: course_files course_files_pkey; Type: CONSTRAINT; Schema: public; Owner: -
 --
@@ -311,6 +325,14 @@ ALTER TABLE ONLY public.course_files
     ADD CONSTRAINT course_files_pkey PRIMARY KEY (id);
 
 
+--
+-- Name: courses courses_folder_key; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.courses
+    ADD CONSTRAINT courses_folder_key UNIQUE (folder);
+
+
 --
 -- Name: courses courses_pkey; Type: CONSTRAINT; Schema: public; Owner: -
 --
@@ -505,4 +527,5 @@ ALTER TABLE ONLY public.time_slots
 INSERT INTO public.schema_migrations (version) VALUES
     ('20260928120000'),
     ('20260928150000'),
-    ('20260929090000');
+    ('20260929090000'),
+    ('20260929180000');
diff --git a/frontend/src/components/AppContent.vue b/frontend/src/components/AppContent.vue
index 926e0c1..857b963 100644
--- a/frontend/src/components/AppContent.vue
+++ b/frontend/src/components/AppContent.vue
@@ -12,11 +12,14 @@ import {
 import { Separator } from '@/components/ui/separator'
 import { SidebarInset, SidebarTrigger } from '@/components/ui/sidebar'
 import ThemeToggle from '@/components/ThemeToggle.vue'
+import { formatDuration, useFocus } from '@/services/focus'
 import { locales, setLocale } from '@/services/i18n'
 import { useI18n } from 'vue-i18n'
+import { Pause, Timer } from '@lucide/vue'
 
 const route = useRoute()
 const { locale: currentLocale } = useI18n()
+const { session, elapsed, isRunning } = useFocus()
 
 const selectedLocale = computed(
   () => locales.find((l) => l.lang === currentLocale.value) ?? locales[0],
@@ -30,7 +33,21 @@ const selectedLocale = computed(
       <Separator orientation="vertical" class="mr-2 data-[orientation=vertical]:h-4" />
       <h1 class="font-medium">{{ route.meta.title ? $t(route.meta.title) : '' }}</h1>
 
-      <ThemeToggle class="ml-auto" />
+      <!-- The session running, from any other page -->
+      <RouterLink
+        v-if="session && route.name !== 'pomodoro'"
+        :to="{ name: 'pomodoro' }"
+        class="ml-auto flex max-w-56 items-center gap-2 rounded-full border px-3 py-1 text-sm transition-colors hover:bg-accent"
+        :title="$t('focus.back')"
+      >
+        <Timer v-if="isRunning" class="size-4 shrink-0 animate-pulse text-primary" />
+        <Pause v-else class="size-4 shrink-0 text-muted-foreground" />
+        <span class="font-mono tabular-nums">{{ formatDuration(elapsed) }}</span>
+        <span class="hidden truncate text-muted-foreground sm:inline">
+          {{ session.task?.name ?? $t('focus.free') }}
+        </span>
+      </RouterLink>
+      <ThemeToggle :class="{ 'ml-auto': !session || route.name === 'pomodoro' }" />
       <DropdownMenu>
         <DropdownMenuTrigger as-child>
           <Button variant="outline" class="rounded-lg">
diff --git a/frontend/src/components/calendar/CoursesCalendar.vue b/frontend/src/components/calendar/TasksCalendar.vue
similarity index 82%
rename from frontend/src/components/calendar/CoursesCalendar.vue
rename to frontend/src/components/calendar/TasksCalendar.vue
index fb0e557..d9d29ad 100644
--- a/frontend/src/components/calendar/CoursesCalendar.vue
+++ b/frontend/src/components/calendar/TasksCalendar.vue
@@ -1,11 +1,12 @@
 <script setup lang="ts">
 /**
- * Month calendar of the deadlines of every course. On a phone the days only show dots:
- * the tasks of the selected day are listed under the calendar, on every screen.
+ * Month calendar of the deadlines of the courses and associations of `kinds`. On a phone
+ * the days only show dots: the tasks of the selected day are listed under the calendar,
+ * on every screen. `create` asks for a new task due on the selected day.
  */
 import { computed, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
-import { CalendarCheck, ChevronLeft, ChevronRight } from '@lucide/vue'
+import { CalendarCheck, ChevronLeft, ChevronRight, Plus, Timer } from '@lucide/vue'
 
 import TagBadge from '@/components/course/TagBadge.vue'
 import { Button } from '@/components/ui/button'
@@ -14,7 +15,11 @@ import { useTags } from '@/services/api/tags'
 import { useCalendarTasks } from '@/services/api/tasks'
 import { dayKey, monthWeeks, weeksPeriod } from '@/utils/calendar'
 import { isPast } from '@/utils/dates'
-import type { CalendarTask } from '@/utils/types'
+import { coursePageRoute, focusRoute, tasksTab } from '@/utils/routes'
+import type { CalendarTask, CourseKind } from '@/utils/types'
+
+const props = defineProps<{ kinds: CourseKind[] }>()
+const emit = defineEmits<{ create: [day: Date] }>()
 
 const { locale } = useI18n()
 const { tagsById } = useTags()
@@ -38,6 +43,7 @@ const {
 const tasksByDay = computed(() => {
   const byDay = new Map<string, CalendarTask[]>()
   for (const task of tasks.value ?? []) {
+    if (!props.kinds.includes(task.course_kind)) continue
     const key = dayKey(new Date(task.deadline))
     byDay.set(key, [...(byDay.get(key) ?? []), task])
   }
@@ -54,12 +60,13 @@ const weekdayLabels = computed(() =>
     new Intl.DateTimeFormat(locale.value, { weekday: 'short' }).format(day),
   ),
 )
-const selectedLabel = computed(() => {
+const selectedDate = computed(() => {
   const [year, m, d] = selectedDay.value.split('-').map(Number)
-  return new Intl.DateTimeFormat(locale.value, { dateStyle: 'full' }).format(
-    new Date(year!, m! - 1, d),
-  )
+  return new Date(year!, m! - 1, d)
 })
+const selectedLabel = computed(() =>
+  new Intl.DateTimeFormat(locale.value, { dateStyle: 'full' }).format(selectedDate.value),
+)
 
 function moveMonth(offset: number) {
   const next = new Date(month.value.getFullYear(), month.value.getMonth() + offset, 1)
@@ -91,7 +98,7 @@ function time(task: CalendarTask) {
 }
 
 function taskLink(task: CalendarTask) {
-  return { name: 'course', params: { id: task.course_id }, query: { tab: 'tasks' } }
+  return coursePageRoute({ id: task.course_id, kind: task.course_kind }, tasksTab(task.course_kind))
 }
 </script>
 
@@ -208,8 +215,12 @@ function taskLink(task: CalendarTask) {
     </p>
 
     <Card>
-      <CardHeader>
+      <CardHeader class="flex flex-row items-center justify-between gap-2">
         <CardTitle class="text-base first-letter:uppercase">{{ selectedLabel }}</CardTitle>
+        <Button variant="outline" size="sm" @click="emit('create', selectedDate)">
+          <Plus />
+          {{ $t('calendar.add-that-day') }}
+        </Button>
       </CardHeader>
       <CardContent>
         <div
@@ -220,10 +231,10 @@ function taskLink(task: CalendarTask) {
           {{ $t('calendar.nothing') }}
         </div>
         <ul v-else class="flex flex-col gap-3">
-          <li v-for="task in selectedTasks" :key="task.task_id">
+          <li v-for="task in selectedTasks" :key="task.task_id" class="flex items-start gap-2">
             <RouterLink
               :to="taskLink(task)"
-              class="flex flex-col gap-1 border-l-2 pl-3 hover:underline"
+              class="flex min-w-0 flex-1 flex-col gap-1 border-l-2 pl-3 hover:underline"
               :style="{ borderLeftColor: taskColor(task) }"
             >
               <span
@@ -245,6 +256,19 @@ function taskLink(task: CalendarTask) {
                 </template>
               </span>
             </RouterLink>
+            <Button
+              v-if="!task.done"
+              variant="ghost"
+              size="icon-sm"
+              class="shrink-0"
+              :title="$t('focus.start')"
+              as-child
+            >
+              <RouterLink :to="focusRoute(task.task_id)">
+                <Timer />
+                <span class="sr-only">{{ $t('focus.start') }}</span>
+              </RouterLink>
+            </Button>
           </li>
         </ul>
       </CardContent>
diff --git a/frontend/src/components/calendar/TodoList.vue b/frontend/src/components/calendar/TodoList.vue
new file mode 100644
index 0000000..c0da214
--- /dev/null
+++ b/frontend/src/components/calendar/TodoList.vue
@@ -0,0 +1,185 @@
+<script setup lang="ts">
+/**
+ * Everything left to do in the courses and associations of `kinds`: the late tasks,
+ * today's, this week's, the later ones and the ones without deadline. Each task (and
+ * subtask) can be checked, or worked on with the pomodoro.
+ */
+import { computed } from 'vue'
+import { useI18n } from 'vue-i18n'
+import { toast } from 'vue-sonner'
+import { ListTodo, Timer } from '@lucide/vue'
+
+import TagBadge from '@/components/course/TagBadge.vue'
+import { Button } from '@/components/ui/button'
+import { Checkbox } from '@/components/ui/checkbox'
+import { Skeleton } from '@/components/ui/skeleton'
+import { useTags } from '@/services/api/tags'
+import { toTaskBody, useAnyTaskMutations, useTodoTasks } from '@/services/api/tasks'
+import { useFocus } from '@/services/focus'
+import { dayKey } from '@/utils/calendar'
+import { formatDateTime, formatRelative, isPast } from '@/utils/dates'
+import { coursePageRoute, focusRoute, tasksTab } from '@/utils/routes'
+import type { CourseKind, Task, TodoTask } from '@/utils/types'
+
+const props = defineProps<{ kinds: CourseKind[] }>()
+
+const { t, locale } = useI18n()
+const { tagsById } = useTags()
+const { data, isPending, isError, refetch } = useTodoTasks()
+const { update } = useAnyTaskMutations()
+const { session } = useFocus()
+
+const GROUPS = ['late', 'today', 'week', 'later', 'undated'] as const
+type Group = (typeof GROUPS)[number]
+
+function groupOf(task: Task): Group {
+  if (!task.deadline) return 'undated'
+  if (isPast(task.deadline)) return 'late'
+  const deadline = new Date(task.deadline)
+  if (dayKey(deadline) === dayKey(new Date())) return 'today'
+  return deadline.getTime() - Date.now() < 7 * 24 * 3600 * 1000 ? 'week' : 'later'
+}
+
+/** Already sorted by deadline by the backend */
+const groups = computed(() => {
+  const byGroup = new Map<Group, TodoTask[]>()
+  for (const todo of data.value ?? []) {
+    if (!props.kinds.includes(todo.course.kind)) continue
+    const group = groupOf(todo.task)
+    byGroup.set(group, [...(byGroup.get(group) ?? []), todo])
+  }
+  return GROUPS.filter((group) => byGroup.has(group)).map((group) => ({
+    group,
+    todos: byGroup.get(group)!,
+  }))
+})
+
+async function setDone(courseId: number, task: Task, done: boolean) {
+  try {
+    await update.mutateAsync({ courseId, id: task.id, body: toTaskBody(task, { done }) })
+  } catch {
+    toast.error(t('tasks.save-error'))
+  }
+}
+
+function inFocus(task: Task) {
+  return session.value?.task?.task_id === task.id
+}
+</script>
+
+<template>
+  <div class="flex flex-col gap-4">
+    <div v-if="isPending" class="flex flex-col gap-2">
+      <Skeleton v-for="i in 4" :key="i" class="h-14 rounded-lg" />
+    </div>
+
+    <p v-else-if="isError" class="text-sm text-destructive">
+      {{ $t('tasks.load-error') }}
+      <Button variant="link" size="sm" @click="refetch()">{{ $t('common.retry') }}</Button>
+    </p>
+
+    <div
+      v-else-if="!groups.length"
+      class="flex flex-col items-center gap-2 py-6 text-center text-sm text-muted-foreground"
+    >
+      <ListTodo class="size-6" />
+      {{ $t('calendar.todo.empty') }}
+    </div>
+
+    <section v-for="{ group, todos } in groups" v-else :key="group" class="flex flex-col gap-2">
+      <h3
+        class="text-xs font-semibold tracking-wide uppercase"
+        :class="group === 'late' ? 'text-destructive' : 'text-muted-foreground'"
+      >
+        {{ $t(`calendar.todo.${group}`) }}
+        <span class="font-normal">· {{ todos.length }}</span>
+      </h3>
+      <ul class="flex flex-col gap-2">
+        <li
+          v-for="{ course, task } in todos"
+          :key="task.id"
+          class="flex flex-col gap-1.5 rounded-lg border bg-card p-2.5"
+        >
+          <div class="flex items-start gap-2.5">
+            <Checkbox
+              class="mt-0.5"
+              :model-value="task.done"
+              :aria-label="$t('tasks.done')"
+              @update:model-value="setDone(course.id, task, $event === true)"
+            />
+            <div class="flex min-w-0 flex-1 flex-col gap-1">
+              <RouterLink
+                :to="coursePageRoute(course, tasksTab(course.kind))"
+                class="text-sm leading-snug font-medium hover:underline"
+              >
+                {{ task.name }}
+              </RouterLink>
+              <span class="flex flex-wrap items-center gap-1.5 text-xs text-muted-foreground">
+                <span class="font-mono">{{ course.code ?? course.name }}</span>
+                <template v-if="task.deadline">
+                  ·
+                  <span
+                    :class="{ 'font-medium text-destructive': group === 'late' }"
+                    :title="formatDateTime(task.deadline, locale)"
+                  >
+                    {{ formatRelative(task.deadline, locale) }}
+                  </span>
+                </template>
+                <template v-for="tagId in task.tag_ids" :key="tagId">
+                  <TagBadge v-if="tagsById.get(tagId)" :tag="tagsById.get(tagId)!" />
+                </template>
+              </span>
+            </div>
+            <Button
+              variant="ghost"
+              size="icon-sm"
+              class="shrink-0"
+              :class="{ 'text-primary': inFocus(task) }"
+              :title="$t('focus.start')"
+              as-child
+            >
+              <RouterLink :to="focusRoute(task.id)">
+                <Timer :class="{ 'animate-pulse': inFocus(task) }" />
+                <span class="sr-only">{{ $t('focus.start') }}</span>
+              </RouterLink>
+            </Button>
+          </div>
+
+          <ul v-if="task.subtasks.length" class="ml-6.5 flex flex-col gap-0.5 border-l pl-2.5">
+            <li
+              v-for="subtask in task.subtasks"
+              :key="subtask.id"
+              class="group flex items-center gap-2 text-sm"
+            >
+              <Checkbox
+                :model-value="subtask.done"
+                :aria-label="$t('tasks.done')"
+                @update:model-value="setDone(course.id, subtask, $event === true)"
+              />
+              <span
+                class="min-w-0 flex-1 truncate"
+                :class="{ 'text-muted-foreground line-through': subtask.done }"
+              >
+                {{ subtask.name }}
+              </span>
+              <Button
+                v-if="!subtask.done"
+                variant="ghost"
+                size="icon-sm"
+                class="size-7 shrink-0 opacity-0 transition-opacity group-focus-within:opacity-100 group-hover:opacity-100 [@media(hover:none)]:opacity-100"
+                :class="{ 'text-primary opacity-100': inFocus(subtask) }"
+                :title="$t('focus.start')"
+                as-child
+              >
+                <RouterLink :to="focusRoute(subtask.id)">
+                  <Timer :class="{ 'animate-pulse': inFocus(subtask) }" />
+                  <span class="sr-only">{{ $t('focus.start') }}</span>
+                </RouterLink>
+              </Button>
+            </li>
+          </ul>
+        </li>
+      </ul>
+    </section>
+  </div>
+</template>
diff --git a/frontend/src/components/course/AssociationDeadlinesTab.vue b/frontend/src/components/course/AssociationDeadlinesTab.vue
new file mode 100644
index 0000000..b0b09f3
--- /dev/null
+++ b/frontend/src/components/course/AssociationDeadlinesTab.vue
@@ -0,0 +1,190 @@
+<script setup lang="ts">
+/**
+ * Deadlines of an association: its week, with its slots (added by selecting a time range)
+ * and the deadlines of each day, then the list of its tasks.
+ */
+import { computed, ref } from 'vue'
+import { useI18n } from 'vue-i18n'
+import { toast } from 'vue-sonner'
+import { ChevronLeft, ChevronRight } from '@lucide/vue'
+
+import ConfirmDeleteDialog from '@/components/ConfirmDeleteDialog.vue'
+import CourseTasksTab from '@/components/course/CourseTasksTab.vue'
+import SlotFormDialog from '@/components/schedule/SlotFormDialog.vue'
+import WeekTimetable from '@/components/timetable/WeekTimetable.vue'
+import { Button } from '@/components/ui/button'
+import { useDeleteSlot } from '@/services/api/courses'
+import { useTags } from '@/services/api/tags'
+import { useCalendarTasks } from '@/services/api/tasks'
+import { dayKey, startOfWeek, weeksPeriod } from '@/utils/calendar'
+import { isPast } from '@/utils/dates'
+import { toHourMinutes, type SlotSelection } from '@/utils/timetable'
+import type { CalendarTask, Course, TimeSlot } from '@/utils/types'
+
+const props = defineProps<{ course: Course }>()
+
+const { t, locale } = useI18n()
+const { tagsById } = useTags()
+const deleteSlot = useDeleteSlot()
+
+const courses = computed(() => [props.course])
+
+/** Monday of the week shown */
+const monday = ref(startOfWeek(new Date()))
+/** The 7 days of the week, the timetable shows the first 5 */
+const week = computed(() =>
+  Array.from({ length: 7 }, (_, i) => {
+    const day = new Date(monday.value)
+    day.setDate(day.getDate() + i)
+    return day
+  }),
+)
+
+function moveWeek(offset: number) {
+  const next = new Date(monday.value)
+  next.setDate(next.getDate() + offset * 7)
+  monday.value = next
+}
+
+const weekLabel = computed(() => {
+  const format = new Intl.DateTimeFormat(locale.value, { day: 'numeric', month: 'long' })
+  return `${format.format(week.value[0]!)} – ${format.format(week.value[6]!)}`
+})
+
+const { data: tasks } = useCalendarTasks(() => weeksPeriod([week.value]))
+
+const tasksByDay = computed(() => {
+  const byDay = new Map<string, CalendarTask[]>()
+  for (const task of tasks.value ?? []) {
+    if (task.course_id !== props.course.id) continue
+    const key = dayKey(new Date(task.deadline))
+    byDay.set(key, [...(byDay.get(key) ?? []), task])
+  }
+  return byDay
+})
+
+/** Deadlines of the weekend, not shown by the timetable */
+const weekendTasks = computed(() =>
+  week.value.slice(5).flatMap((day) => tasksByDay.value.get(dayKey(day)) ?? []),
+)
+
+function taskColor(task: CalendarTask) {
+  return tagsById.value.get(task.tag_ids[0] ?? -1)?.color ?? 'var(--primary)'
+}
+
+function time(task: CalendarTask) {
+  return new Intl.DateTimeFormat(locale.value, { hour: '2-digit', minute: '2-digit' }).format(
+    new Date(task.deadline),
+  )
+}
+
+const slotFormOpen = ref(false)
+const slotSelection = ref<SlotSelection>()
+
+function onSelect(selection: SlotSelection) {
+  slotSelection.value = selection
+  slotFormOpen.value = true
+}
+
+const deleteOpen = ref(false)
+const deletedSlot = ref<TimeSlot>()
+const deletedSlotLabel = computed(() => {
+  const slot = deletedSlot.value
+  if (!slot) return ''
+  return `${t(`weekdays.${slot.weekday}`)} ${toHourMinutes(slot.start_time)}–${toHourMinutes(slot.end_time)}`
+})
+
+function askDeleteSlot(slot: TimeSlot) {
+  deletedSlot.value = slot
+  deleteOpen.value = true
+}
+
+async function confirmDeleteSlot() {
+  if (!deletedSlot.value) return
+  try {
+    await deleteSlot.mutateAsync({ courseId: props.course.id, slotId: deletedSlot.value.id })
+    toast.success(t('schedule.slot-deleted'))
+  } catch {
+    toast.error(t('schedule.slot-delete-error'))
+  }
+}
+</script>
+
+<template>
+  <div class="flex min-w-0 flex-col gap-6">
+    <section class="flex min-w-0 flex-col gap-2">
+      <div class="flex flex-wrap items-center gap-2">
+        <h3 class="mr-auto font-medium first-letter:uppercase">{{ weekLabel }}</h3>
+        <Button variant="outline" size="sm" @click="monday = startOfWeek(new Date())">
+          {{ $t('calendar.this-week') }}
+        </Button>
+        <Button
+          variant="outline"
+          size="icon-sm"
+          :title="$t('calendar.previous-week')"
+          @click="moveWeek(-1)"
+        >
+          <ChevronLeft />
+          <span class="sr-only">{{ $t('calendar.previous-week') }}</span>
+        </Button>
+        <Button
+          variant="outline"
+          size="icon-sm"
+          :title="$t('calendar.next-week')"
+          @click="moveWeek(1)"
+        >
+          <ChevronRight />
+          <span class="sr-only">{{ $t('calendar.next-week') }}</span>
+        </Button>
+      </div>
+      <p class="text-sm text-muted-foreground">{{ $t('association.deadlines.hint') }}</p>
+
+      <WeekTimetable
+        :courses="courses"
+        :dates="week.slice(0, 5)"
+        height="34rem"
+        selectable
+        deletable
+        @select="onSelect"
+        @delete="askDeleteSlot"
+      >
+        <template #day="{ date }">
+          <span v-if="date" class="flex min-w-0 flex-col gap-0.5 text-left font-normal">
+            <span
+              v-for="task in tasksByDay.get(dayKey(date)) ?? []"
+              :key="task.task_id"
+              class="truncate rounded border-l-2 px-1 py-0.5 text-xs"
+              :class="{
+                'text-muted-foreground line-through': task.done,
+                'font-medium text-destructive': !task.done && isPast(task.deadline),
+              }"
+              :style="{
+                borderLeftColor: taskColor(task),
+                backgroundColor: `color-mix(in oklab, ${taskColor(task)} 12%, transparent)`,
+              }"
+              :title="`${time(task)} · ${task.name}`"
+            >
+              <span class="tabular-nums opacity-70">{{ time(task) }}</span>
+              {{ task.name }}
+            </span>
+          </span>
+        </template>
+      </WeekTimetable>
+      <p v-if="weekendTasks.length" class="text-sm text-muted-foreground">
+        {{ $t('association.deadlines.weekend') }}
+        <span v-for="task in weekendTasks" :key="task.task_id" class="ml-2 text-foreground">
+          {{ task.name }}
+        </span>
+      </p>
+    </section>
+
+    <CourseTasksTab :course-id="course.id" />
+
+    <SlotFormDialog v-model:open="slotFormOpen" :selection="slotSelection" :course-id="course.id" />
+    <ConfirmDeleteDialog
+      v-model:open="deleteOpen"
+      :title="$t('schedule.delete-slot-title', { slot: deletedSlotLabel })"
+      @confirm="confirmDeleteSlot"
+    />
+  </div>
+</template>
diff --git a/frontend/src/components/course/CourseFilesTab.vue b/frontend/src/components/course/CourseFilesTab.vue
index a57363d..755965a 100644
--- a/frontend/src/components/course/CourseFilesTab.vue
+++ b/frontend/src/components/course/CourseFilesTab.vue
@@ -18,14 +18,15 @@ import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip
 import { useCourseFiles, useLectureNoteMutations } from '@/services/api/course-files'
 import { useTags } from '@/services/api/tags'
 import { formatDate } from '@/utils/dates'
-import type { CourseFile } from '@/utils/types'
+import { noteRoute } from '@/utils/routes'
+import type { Course, CourseFile } from '@/utils/types'
 
-const props = defineProps<{ courseId: number }>()
+const props = defineProps<{ course: Course }>()
 
 const { t, locale } = useI18n()
 const { tagsById } = useTags()
-const { data: files, isPending, isError, refetch } = useCourseFiles(() => props.courseId)
-const { remove } = useLectureNoteMutations(() => props.courseId)
+const { data: files, isPending, isError, refetch } = useCourseFiles(() => props.course.id)
+const { remove } = useLectureNoteMutations(() => props.course.id)
 
 const deleteOpen = ref(false)
 const deletedFile = ref<CourseFile>()
@@ -50,7 +51,7 @@ async function confirmDelete() {
   <Card>
     <CardHeader class="flex flex-row flex-wrap items-start justify-between gap-3">
       <div class="flex flex-col gap-1.5">
-        <CardTitle class="text-base">{{ $t('files.title') }}</CardTitle>
+        <CardTitle class="text-base">{{ $t(`files.title.${course.kind}`) }}</CardTitle>
         <CardDescription>{{ $t('files.description') }}</CardDescription>
       </div>
       <div class="flex gap-2">
@@ -67,7 +68,7 @@ async function confirmDelete() {
           <TooltipContent>{{ $t('files.coming-soon') }}</TooltipContent>
         </Tooltip>
         <Button size="sm" as-child>
-          <RouterLink :to="{ name: 'course-note', params: { id: courseId, noteId: 'new' } }">
+          <RouterLink :to="noteRoute(course, 'new')">
             <Plus />
             {{ $t('notes.new') }}
           </RouterLink>
@@ -105,7 +106,7 @@ async function confirmDelete() {
           />
           <div class="flex min-w-0 flex-1 flex-col gap-1">
             <RouterLink
-              :to="{ name: 'course-note', params: { id: courseId, noteId: file.id } }"
+              :to="noteRoute(course, file.id)"
               class="truncate text-sm font-medium after:absolute after:inset-0 after:content-['']"
             >
               {{ file.name }}
@@ -134,13 +135,7 @@ async function confirmDelete() {
               :title="$t('common.edit')"
               as-child
             >
-              <RouterLink
-                :to="{
-                  name: 'course-note',
-                  params: { id: courseId, noteId: file.id },
-                  query: { edit: '1' },
-                }"
-              >
+              <RouterLink :to="noteRoute(course, file.id, true)">
                 <Pencil />
                 <span class="sr-only">{{ $t('common.edit') }}</span>
               </RouterLink>
diff --git a/frontend/src/components/course/CourseTasksTab.vue b/frontend/src/components/course/CourseTasksTab.vue
index b9ff6c3..1ba8d18 100644
--- a/frontend/src/components/course/CourseTasksTab.vue
+++ b/frontend/src/components/course/CourseTasksTab.vue
@@ -1,12 +1,22 @@
 <script setup lang="ts">
 /**
  * Homework, exams and anything to do for the course, with their subtasks. The backend
- * sorts them (not done first, then by deadline) and nests the subtasks.
+ * sorts them (not done first, then by deadline) and nests the subtasks. Each one can be
+ * worked on with the pomodoro.
  */
 import { ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { toast } from 'vue-sonner'
-import { CalendarClock, ClipboardList, ExternalLink, Pencil, Plus, Trash2 } from '@lucide/vue'
+import {
+  CalendarClock,
+  ClipboardList,
+  ExternalLink,
+  Hourglass,
+  Pencil,
+  Plus,
+  Timer,
+  Trash2,
+} from '@lucide/vue'
 
 import ConfirmDeleteDialog from '@/components/ConfirmDeleteDialog.vue'
 import TagBadge from '@/components/course/TagBadge.vue'
@@ -18,7 +28,9 @@ import { Input } from '@/components/ui/input'
 import { Skeleton } from '@/components/ui/skeleton'
 import { useTags } from '@/services/api/tags'
 import { toTaskBody, useCourseTasks, useTaskMutations } from '@/services/api/tasks'
+import { formatSpent, useFocus } from '@/services/focus'
 import { formatDateTime, isPast } from '@/utils/dates'
+import { focusRoute } from '@/utils/routes'
 import type { Task } from '@/utils/types'
 
 const props = defineProps<{ courseId: number }>()
@@ -27,6 +39,11 @@ const { t, locale } = useI18n()
 const { tagsById } = useTags()
 const { data, isPending, isError, refetch } = useCourseTasks(() => props.courseId)
 const { create, update, remove } = useTaskMutations(() => props.courseId)
+const { session } = useFocus()
+
+function inFocus(task: Task) {
+  return session.value?.task?.task_id === task.id
+}
 
 const formOpen = ref(false)
 const editedTask = ref<Task>()
@@ -141,6 +158,13 @@ function isLate(task: Task) {
               {{ formatDateTime(task.deadline, locale) }}
               <template v-if="isLate(task)">· {{ $t('tasks.late') }}</template>
             </span>
+            <span
+              v-if="task.time_spent >= 60"
+              class="flex items-center gap-1 text-xs text-muted-foreground"
+            >
+              <Hourglass class="size-3.5" />
+              {{ $t('tasks.time-spent', { time: formatSpent(task.time_spent) }) }}
+            </span>
             <p v-if="task.description" class="text-sm whitespace-pre-line text-muted-foreground">
               {{ task.description }}
             </p>
@@ -159,6 +183,19 @@ function isLate(task: Task) {
             </ul>
           </div>
           <div class="flex shrink-0 gap-1">
+            <Button
+              v-if="!task.done"
+              variant="ghost"
+              size="icon-sm"
+              :class="{ 'text-primary': inFocus(task) }"
+              :title="$t('focus.start')"
+              as-child
+            >
+              <RouterLink :to="focusRoute(task.id)">
+                <Timer :class="{ 'animate-pulse': inFocus(task) }" />
+                <span class="sr-only">{{ $t('focus.start') }}</span>
+              </RouterLink>
+            </Button>
             <Button
               variant="ghost"
               size="icon-sm"
@@ -207,8 +244,23 @@ function isLate(task: Task) {
               <TagBadge v-if="tagsById.get(tagId)" :tag="tagsById.get(tagId)!" />
             </template>
             <div
-              class="ml-auto flex gap-1 opacity-0 transition-opacity group-focus-within:opacity-100 group-hover:opacity-100"
+              class="ml-auto flex gap-1 opacity-0 transition-opacity group-focus-within:opacity-100 group-hover:opacity-100 [@media(hover:none)]:opacity-100"
+              :class="{ 'opacity-100': inFocus(subtask) }"
             >
+              <Button
+                v-if="!subtask.done && !task.done"
+                variant="ghost"
+                size="icon-sm"
+                class="size-7"
+                :class="{ 'text-primary': inFocus(subtask) }"
+                :title="$t('focus.start')"
+                as-child
+              >
+                <RouterLink :to="focusRoute(subtask.id)">
+                  <Timer :class="{ 'animate-pulse': inFocus(subtask) }" />
+                  <span class="sr-only">{{ $t('focus.start') }}</span>
+                </RouterLink>
+              </Button>
               <Button
                 variant="ghost"
                 size="icon-sm"
diff --git a/frontend/src/components/course/TaskFormDialog.vue b/frontend/src/components/course/TaskFormDialog.vue
index 041806e..5b77008 100644
--- a/frontend/src/components/course/TaskFormDialog.vue
+++ b/frontend/src/components/course/TaskFormDialog.vue
@@ -1,7 +1,8 @@
 <script setup lang="ts">
 /**
  * Creates a task (or a subtask of `parentId`), or edits `task` when given. A task needs
- * at least one tag, a subtask may have none.
+ * at least one tag, a subtask may have none. Without `courseId` the course (or the
+ * association) is picked in the form. `defaultDeadline` (ISO) prefills a new task.
  */
 import { computed, ref, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
@@ -18,6 +19,15 @@ import {
 } from '@/components/ui/dialog'
 import { Input } from '@/components/ui/input'
 import { Label } from '@/components/ui/label'
+import {
+  Select,
+  SelectContent,
+  SelectGroup,
+  SelectItem,
+  SelectLabel,
+  SelectTrigger,
+  SelectValue,
+} from '@/components/ui/select'
 import {
   TagsInput,
   TagsInputInput,
@@ -26,17 +36,33 @@ import {
   TagsInputItemText,
 } from '@/components/ui/tags-input'
 import { Textarea } from '@/components/ui/textarea'
+import { useCourses } from '@/services/api/courses'
 import { useTags } from '@/services/api/tags'
-import { useTaskMutations } from '@/services/api/tasks'
+import { useAnyTaskMutations } from '@/services/api/tasks'
 import { fromDateTimeInput, toDateTimeInput } from '@/utils/dates'
 import type { Task, TaskBody } from '@/utils/types'
 
-const props = defineProps<{ courseId: number; task?: Task; parentId?: number }>()
+const props = defineProps<{
+  courseId?: number
+  task?: Task
+  parentId?: number
+  defaultDeadline?: string
+}>()
 const open = defineModel<boolean>('open', { required: true })
 
 const { t } = useI18n()
 const { data: tags } = useTags('task')
-const { create, update } = useTaskMutations(() => props.courseId)
+const { data: courses } = useCourses()
+const { create, update } = useAnyTaskMutations()
+
+/** Picked in the form when not given */
+const pickedCourseId = ref<number>()
+const courseId = computed(() => props.task?.course_id ?? props.courseId ?? pickedCourseId.value)
+const courseGroups = computed(() =>
+  (['course', 'association'] as const)
+    .map((kind) => ({ kind, courses: courses.value?.filter((c) => c.kind === kind) ?? [] }))
+    .filter((group) => group.courses.length),
+)
 
 const isSubtask = computed(() => (props.task ? props.task.parent_id != null : !!props.parentId))
 
@@ -53,7 +79,8 @@ watch(
     if (!isOpen) return
     name.value = props.task?.name ?? ''
     tagIds.value = [...(props.task?.tag_ids ?? [])]
-    deadline.value = props.task?.deadline ? toDateTimeInput(props.task.deadline) : ''
+    const initialDeadline = props.task ? props.task.deadline : props.defaultDeadline
+    deadline.value = initialDeadline ? toDateTimeInput(initialDeadline) : ''
     description.value = props.task?.description ?? ''
     links.value = [...(props.task?.links ?? [])]
     submitted.value = false
@@ -69,6 +96,7 @@ function toggleTag(id: number) {
 
 // Same rules as the backend, checked here to point at the faulty field
 const errors = computed(() => ({
+  course: courseId.value === undefined,
   name: !name.value.trim(),
   tags: !isSubtask.value && tagIds.value.length === 0,
   links: links.value.some((link) => !/^https?:\/\//.test(link.trim())),
@@ -78,7 +106,7 @@ const isPending = computed(() => create.isPending.value || update.isPending.valu
 
 async function submit() {
   submitted.value = true
-  if (Object.values(errors.value).some(Boolean)) return
+  if (Object.values(errors.value).some(Boolean) || courseId.value === undefined) return
 
   const body: TaskBody = {
     name: name.value.trim(),
@@ -90,10 +118,13 @@ async function submit() {
   }
   try {
     if (props.task) {
-      await update.mutateAsync({ id: props.task.id, body })
+      await update.mutateAsync({ courseId: courseId.value, id: props.task.id, body })
       toast.success(t('tasks.updated'))
     } else {
-      await create.mutateAsync({ ...body, parent_id: props.parentId ?? null })
+      await create.mutateAsync({
+        courseId: courseId.value,
+        body: { ...body, parent_id: props.parentId ?? null },
+      })
       toast.success(t('tasks.created'))
     }
     open.value = false
@@ -116,6 +147,30 @@ async function submit() {
       </DialogHeader>
 
       <form id="task-form" class="flex flex-col gap-4" novalidate @submit.prevent="submit">
+        <div v-if="!task && props.courseId === undefined" class="flex flex-col gap-2">
+          <Label for="task-course">{{ $t('tasks.form.course') }}</Label>
+          <Select v-model="pickedCourseId">
+            <SelectTrigger
+              id="task-course"
+              class="w-full"
+              :aria-invalid="submitted && errors.course"
+            >
+              <SelectValue :placeholder="$t('tasks.form.course-placeholder')" />
+            </SelectTrigger>
+            <SelectContent>
+              <SelectGroup v-for="group in courseGroups" :key="group.kind">
+                <SelectLabel>{{ $t(`nav.${group.kind}s`) }}</SelectLabel>
+                <SelectItem v-for="course in group.courses" :key="course.id" :value="course.id">
+                  {{ course.name }}
+                  <span v-if="course.code" class="font-mono text-xs text-muted-foreground">
+                    {{ course.code }}
+                  </span>
+                </SelectItem>
+              </SelectGroup>
+            </SelectContent>
+          </Select>
+        </div>
+
         <div class="flex flex-col gap-2">
           <Label for="task-name">{{ $t('tasks.form.name') }}</Label>
           <Input
diff --git a/frontend/src/components/courses/CourseFormDialog.vue b/frontend/src/components/courses/CourseFormDialog.vue
index b1dd0bb..b26c481 100644
--- a/frontend/src/components/courses/CourseFormDialog.vue
+++ b/frontend/src/components/courses/CourseFormDialog.vue
@@ -1,7 +1,7 @@
 <script setup lang="ts">
 /**
- * Creates a course, or edits `course` when given. Slots are not edited here but by
- * selecting a time range in the schedule.
+ * Creates a course or an association, or edits `course` when given. Slots are not edited
+ * here but by selecting a time range in the schedule. An association has no teacher.
  */
 import { computed, ref, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
@@ -26,12 +26,16 @@ import {
   TagsInputItemText,
 } from '@/components/ui/tags-input'
 import { useCreateCourse, useUpdateCourse } from '@/services/api/courses'
-import type { Course, CourseBody } from '@/utils/types'
+import type { Course, CourseBody, CourseKind } from '@/utils/types'
 
-const props = defineProps<{ course?: Course }>()
+const props = defineProps<{ kind: CourseKind; course?: Course }>()
 const open = defineModel<boolean>('open', { required: true })
 
 const { t } = useI18n()
+
+/** Prefix of the texts of the form */
+const k = computed(() => (props.kind === 'course' ? 'courses' : 'associations'))
+const isCourse = computed(() => props.kind === 'course')
 const createCourse = useCreateCourse()
 const updateCourse = useUpdateCourse()
 
@@ -61,7 +65,7 @@ const errors = computed(() => {
   const url = mainPageUrl.value.trim()
   return {
     name: !name.value.trim(),
-    teachers: !teachers.value.some((teacher) => teacher.trim()),
+    teachers: isCourse.value && !teachers.value.some((teacher) => teacher.trim()),
     mainPage: url !== '' && !/^https?:\/\//.test(url),
   }
 })
@@ -74,6 +78,7 @@ async function submit() {
   if (!isValid.value) return
 
   const body: CourseBody = {
+    kind: props.kind,
     name: name.value.trim(),
     code: code.value.trim() || null,
     teachers: teachers.value.map((teacher) => teacher.trim()).filter(Boolean),
@@ -83,14 +88,14 @@ async function submit() {
   try {
     if (props.course) {
       await updateCourse.mutateAsync({ id: props.course.id, body })
-      toast.success(t('courses.updated'))
+      toast.success(t(`${k.value}.updated`))
     } else {
       await createCourse.mutateAsync(body)
-      toast.success(t('courses.created'))
+      toast.success(t(`${k.value}.created`))
     }
     open.value = false
   } catch (err) {
-    toast.error(t('courses.save-error'), {
+    toast.error(t(`${k.value}.save-error`), {
       description: err instanceof Error ? err.message : undefined,
     })
   }
@@ -101,8 +106,8 @@ async function submit() {
   <Dialog v-model:open="open">
     <DialogContent class="max-h-[90svh] overflow-y-auto sm:max-w-lg">
       <DialogHeader>
-        <DialogTitle>{{ course ? $t('courses.edit') : $t('courses.new') }}</DialogTitle>
-        <DialogDescription>{{ $t('courses.form.description') }}</DialogDescription>
+        <DialogTitle>{{ course ? $t(`${k}.edit`) : $t(`${k}.new`) }}</DialogTitle>
+        <DialogDescription>{{ $t(`${k}.form.description`) }}</DialogDescription>
       </DialogHeader>
 
       <form id="course-form" class="flex flex-col gap-5" novalidate @submit.prevent="submit">
@@ -112,7 +117,7 @@ async function submit() {
             <Input
               id="course-name"
               v-model="name"
-              :placeholder="$t('courses.form.name-placeholder')"
+              :placeholder="$t(`${k}.form.name-placeholder`)"
               :aria-invalid="submitted && errors.name"
             />
             <p v-if="submitted && errors.name" class="text-sm text-destructive">
@@ -121,7 +126,7 @@ async function submit() {
           </div>
           <div class="flex flex-col gap-2">
             <Label for="course-code">
-              {{ $t('courses.form.code') }}
+              {{ $t(`${k}.form.code`) }}
               <span class="font-normal text-muted-foreground">
                 ({{ $t('courses.form.optional') }})
               </span>
@@ -129,12 +134,12 @@ async function submit() {
             <Input
               id="course-code"
               v-model="code"
-              :placeholder="$t('courses.form.code-placeholder')"
+              :placeholder="$t(`${k}.form.code-placeholder`)"
             />
           </div>
         </div>
 
-        <div class="flex flex-col gap-2">
+        <div v-if="isCourse" class="flex flex-col gap-2">
           <Label for="course-teachers">{{ $t('courses.form.teachers') }}</Label>
           <TagsInput
             v-model="teachers"
@@ -168,7 +173,7 @@ async function submit() {
             id="course-main-page"
             v-model="mainPageUrl"
             type="url"
-            :placeholder="$t('courses.form.main-page-placeholder')"
+            :placeholder="$t(`${k}.form.main-page-placeholder`)"
             :aria-invalid="submitted && errors.mainPage"
           />
           <p v-if="submitted && errors.mainPage" class="text-sm text-destructive">
diff --git a/frontend/src/components/schedule/SlotFormDialog.vue b/frontend/src/components/schedule/SlotFormDialog.vue
index 9d415ab..bf1078d 100644
--- a/frontend/src/components/schedule/SlotFormDialog.vue
+++ b/frontend/src/components/schedule/SlotFormDialog.vue
@@ -1,5 +1,8 @@
 <script setup lang="ts">
-/** Adds a slot to a course, prefilled with the time range selected in the schedule */
+/**
+ * Adds a slot to a course or an association, prefilled with the time range selected in
+ * the schedule. `courseId` picks the course.
+ */
 import { computed, ref, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { toast } from 'vue-sonner'
@@ -18,7 +21,9 @@ import { Label } from '@/components/ui/label'
 import {
   Select,
   SelectContent,
+  SelectGroup,
   SelectItem,
+  SelectLabel,
   SelectTrigger,
   SelectValue,
 } from '@/components/ui/select'
@@ -33,7 +38,7 @@ import {
   type SlotSelection,
 } from '@/utils/timetable'
 
-const props = defineProps<{ selection?: SlotSelection }>()
+const props = defineProps<{ selection?: SlotSelection; courseId?: number }>()
 const open = defineModel<boolean>('open', { required: true })
 
 const { t } = useI18n()
@@ -41,7 +46,13 @@ const { data: courses } = useCourses()
 const { data: tags } = useTags('slot')
 const addSlot = useAddSlot()
 
-const courseId = ref<number>()
+const groups = computed(() =>
+  (['course', 'association'] as const)
+    .map((kind) => ({ kind, courses: courses.value?.filter((c) => c.kind === kind) ?? [] }))
+    .filter((group) => group.courses.length),
+)
+
+const pickedCourseId = ref<number>()
 const tagId = ref<number>()
 const weekday = ref(1)
 const start = ref('')
@@ -56,8 +67,10 @@ watch(
     weekday.value = props.selection?.weekday ?? 1
     start.value = props.selection?.start ?? '08:15'
     end.value = props.selection?.end ?? '10:00'
-    if (!courses.value?.some((course) => course.id === courseId.value)) {
-      courseId.value = courses.value?.[0]?.id
+    if (props.courseId !== undefined) {
+      pickedCourseId.value = props.courseId
+    } else if (!courses.value?.some((course) => course.id === pickedCourseId.value)) {
+      pickedCourseId.value = courses.value?.[0]?.id
     }
     tagId.value ??= tags.value[0]?.id
     submitted.value = false
@@ -70,7 +83,7 @@ const errors = computed(() => {
   const startMinutes = toMinutes(start.value)
   const endMinutes = toMinutes(end.value)
   return {
-    course: courseId.value === undefined,
+    course: pickedCourseId.value === undefined,
     time:
       !start.value ||
       !end.value ||
@@ -83,11 +96,11 @@ const errors = computed(() => {
 async function submit() {
   submitted.value = true
   if (errors.value.course || errors.value.time) return
-  if (courseId.value === undefined || tagId.value === undefined) return
+  if (pickedCourseId.value === undefined || tagId.value === undefined) return
 
   try {
     await addSlot.mutateAsync({
-      courseId: courseId.value,
+      courseId: pickedCourseId.value,
       body: {
         tag_id: tagId.value,
         weekday: weekday.value,
@@ -116,17 +129,20 @@ async function submit() {
       <form id="slot-form" class="grid grid-cols-2 gap-4" novalidate @submit.prevent="submit">
         <div class="col-span-2 flex flex-col gap-2">
           <Label for="slot-course">{{ $t('schedule.form.course') }}</Label>
-          <Select v-model="courseId">
+          <Select v-model="pickedCourseId">
             <SelectTrigger id="slot-course" class="w-full">
               <SelectValue />
             </SelectTrigger>
             <SelectContent>
-              <SelectItem v-for="course in courses" :key="course.id" :value="course.id">
-                {{ course.name }}
-                <span v-if="course.code" class="font-mono text-xs text-muted-foreground">
-                  {{ course.code }}
-                </span>
-              </SelectItem>
+              <SelectGroup v-for="group in groups" :key="group.kind">
+                <SelectLabel>{{ $t(`nav.${group.kind}s`) }}</SelectLabel>
+                <SelectItem v-for="course in group.courses" :key="course.id" :value="course.id">
+                  {{ course.name }}
+                  <span v-if="course.code" class="font-mono text-xs text-muted-foreground">
+                    {{ course.code }}
+                  </span>
+                </SelectItem>
+              </SelectGroup>
             </SelectContent>
           </Select>
         </div>
diff --git a/frontend/src/components/timetable/WeekTimetable.vue b/frontend/src/components/timetable/WeekTimetable.vue
index d3992b7..c746b92 100644
--- a/frontend/src/components/timetable/WeekTimetable.vue
+++ b/frontend/src/components/timetable/WeekTimetable.vue
@@ -5,8 +5,11 @@
  *  - `selectable`: a time range can be selected with the pointer, emitted as `select`
  *  - `linkToCourse`: clicking a slot opens the page of its course
  *  - `deletable`: each slot gets a button emitting `delete` (not with `linkToCourse`)
+ *  - `dates`: the days of a real week (monday to friday), shown in the header. The `day`
+ *    slot adds content under the header of each day (e.g. its deadlines).
  */
 import { computed, ref } from 'vue'
+import { useI18n } from 'vue-i18n'
 import { RouterLink } from 'vue-router'
 import { X } from '@lucide/vue'
 
@@ -22,6 +25,7 @@ import {
   toMinutes,
   type SlotSelection,
 } from '@/utils/timetable'
+import { coursePageRoute } from '@/utils/routes'
 import type { Course, Tag, TimeSlot } from '@/utils/types'
 
 const props = withDefaults(
@@ -32,6 +36,7 @@ const props = withDefaults(
     deletable?: boolean
     /** Css height of the day columns */
     height?: string
+    dates?: Date[]
   }>(),
   { height: '55rem' },
 )
@@ -41,8 +46,20 @@ const emit = defineEmits<{
   delete: [slot: TimeSlot, course: Course]
 }>()
 
+defineSlots<{ day?: (props: { weekday: number; date?: Date }) => unknown }>()
+
+const { locale } = useI18n()
 const { tagsById } = useTags()
 
+/** "5 oct." */
+function dayOfMonth(date: Date) {
+  return new Intl.DateTimeFormat(locale.value, { day: 'numeric', month: 'short' }).format(date)
+}
+
+function isToday(date: Date) {
+  return date.toDateString() === new Date().toDateString()
+}
+
 const HOURS = Array.from(
   { length: DAY_END_HOUR - DAY_START_HOUR + 1 },
   (_, i) => DAY_START_HOUR + i,
@@ -160,11 +177,25 @@ function endSelection() {
       <!-- Header: weekdays -->
       <div class="border-b" />
       <div
-        v-for="day in days"
+        v-for="(day, index) in days"
         :key="day.weekday"
-        class="border-b border-l px-2 py-3 text-center text-sm font-medium"
+        class="flex min-w-0 flex-col gap-1.5 border-b border-l px-2 py-3 text-center text-sm font-medium"
       >
-        {{ $t(`weekdays.${day.weekday}`) }}
+        <span>
+          {{ $t(`weekdays.${day.weekday}`) }}
+          <span
+            v-if="dates?.[index]"
+            class="ml-1 rounded-full px-1.5 py-0.5 text-xs tabular-nums"
+            :class="
+              isToday(dates[index]!)
+                ? 'bg-primary text-primary-foreground'
+                : 'font-normal text-muted-foreground'
+            "
+          >
+            {{ dayOfMonth(dates[index]!) }}
+          </span>
+        </span>
+        <slot name="day" :weekday="day.weekday" :date="dates?.[index]" />
       </div>
 
       <!-- Hours column -->
@@ -202,7 +233,7 @@ function endSelection() {
           <TooltipTrigger as-child>
             <component
               :is="linkToCourse ? RouterLink : 'div'"
-              :to="linkToCourse ? { name: 'course', params: { id: block.course.id } } : undefined"
+              :to="linkToCourse ? coursePageRoute(block.course) : undefined"
               class="group absolute flex flex-col gap-0.5 overflow-hidden rounded-md border-l-4 px-2 py-1 text-foreground transition-shadow hover:z-10 hover:shadow-md"
               :class="{ 'cursor-pointer': linkToCourse, 'cursor-default': !linkToCourse }"
               :style="blockStyle(block, lane, lanes)"
diff --git a/frontend/src/components/ui/alert-dialog/AlertDialogContent.vue b/frontend/src/components/ui/alert-dialog/AlertDialogContent.vue
index dc3b226..4b4f4fd 100644
--- a/frontend/src/components/ui/alert-dialog/AlertDialogContent.vue
+++ b/frontend/src/components/ui/alert-dialog/AlertDialogContent.vue
@@ -27,7 +27,7 @@ const forwarded = useForwardPropsEmits(delegatedProps, emits)
       v-bind="forwarded"
       :class="
         cn(
-          'fixed left-1/2 top-1/2 z-50 grid w-full max-w-lg -translate-x-1/2 -translate-y-1/2 gap-4 border bg-background p-6 shadow-lg duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 sm:rounded-lg',
+          'fixed left-1/2 top-1/2 z-50 grid w-full grid-cols-1 max-w-lg -translate-x-1/2 -translate-y-1/2 gap-4 border bg-background p-6 shadow-lg duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 sm:rounded-lg',
           props.class,
         )
       "
diff --git a/frontend/src/components/ui/dialog/DialogContent.vue b/frontend/src/components/ui/dialog/DialogContent.vue
index b2bf24a..4587914 100644
--- a/frontend/src/components/ui/dialog/DialogContent.vue
+++ b/frontend/src/components/ui/dialog/DialogContent.vue
@@ -29,7 +29,7 @@ const forwarded = useForwardPropsEmits(delegatedProps, emits)
       v-bind="forwarded"
       :class="
         cn(
-          'fixed left-1/2 top-1/2 z-50 grid w-full max-w-lg -translate-x-1/2 -translate-y-1/2 gap-4 border bg-background p-6 shadow-lg duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[state=closed]:slide-out-to-left-1/2 data-[state=closed]:slide-out-to-top-[48%] data-[state=open]:slide-in-from-left-1/2 data-[state=open]:slide-in-from-top-[48%] sm:rounded-lg',
+          'fixed left-1/2 top-1/2 z-50 grid w-full grid-cols-1 max-w-lg -translate-x-1/2 -translate-y-1/2 gap-4 border bg-background p-6 shadow-lg duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 sm:rounded-lg',
           props.class,
         )
       "
diff --git a/frontend/src/lib/api.d.ts b/frontend/src/lib/api.d.ts
index c420f6e..325c4e3 100644
--- a/frontend/src/lib/api.d.ts
+++ b/frontend/src/lib/api.d.ts
@@ -75,7 +75,7 @@ export interface paths {
         path?: never
         cookie?: never
       }
-      /** @description A course, without its slots: they are added and removed one by one */
+      /** @description A course or an association, without its slots: they are added and removed one by one */
       requestBody: {
         content: {
           'application/json': components['schemas']['CourseBody']
@@ -127,6 +127,10 @@ export interface paths {
       }
       requestBody?: never
       responses: {
+        /**
+         * @description A course, or an association: both have tasks, files and slots, only the courses have
+         *      teachers and grades.
+         */
         200: {
           headers: {
             [name: string]: unknown
@@ -156,13 +160,17 @@ export interface paths {
         }
         cookie?: never
       }
-      /** @description A course, without its slots: they are added and removed one by one */
+      /** @description A course or an association, without its slots: they are added and removed one by one */
       requestBody: {
         content: {
           'application/json': components['schemas']['CourseBody']
         }
       }
       responses: {
+        /**
+         * @description A course, or an association: both have tasks, files and slots, only the courses have
+         *      teachers and grades.
+         */
         200: {
           headers: {
             [name: string]: unknown
@@ -252,6 +260,10 @@ export interface paths {
         }
       }
       responses: {
+        /**
+         * @description A course, or an association: both have tasks, files and slots, only the courses have
+         *      teachers and grades.
+         */
         200: {
           headers: {
             [name: string]: unknown
@@ -310,6 +322,10 @@ export interface paths {
       }
       requestBody?: never
       responses: {
+        /**
+         * @description A course, or an association: both have tasks, files and slots, only the courses have
+         *      teachers and grades.
+         */
         200: {
           headers: {
             [name: string]: unknown
@@ -603,6 +619,41 @@ export interface paths {
     patch?: never
     trace?: never
   }
+  '/api/tasks/todo': {
+    parameters: {
+      query?: never
+      header?: never
+      path?: never
+      cookie?: never
+    }
+    /** Get the tasks not done of every course and association, with their subtasks, the closest deadline first */
+    get: {
+      parameters: {
+        query?: never
+        header?: never
+        path?: never
+        cookie?: never
+      }
+      requestBody?: never
+      responses: {
+        200: {
+          headers: {
+            [name: string]: unknown
+          }
+          content: {
+            'application/json': components['schemas']['TodoTask'][]
+          }
+        }
+      }
+    }
+    put?: never
+    post?: never
+    delete?: never
+    options?: never
+    head?: never
+    patch?: never
+    trace?: never
+  }
   '/api/courses/{id}/tasks': {
     parameters: {
       query?: never
@@ -785,6 +836,117 @@ export interface paths {
     patch?: never
     trace?: never
   }
+  '/api/tasks/{id}/focus': {
+    parameters: {
+      query?: never
+      header?: never
+      path?: never
+      cookie?: never
+    }
+    get?: never
+    put?: never
+    /**
+     * Start a focus session on a task, and its TimeTagger record
+     * @description The session starts even when TimeTagger fails: see `timetagger_error`.
+     */
+    post: {
+      parameters: {
+        query?: never
+        header?: never
+        path: {
+          id: number
+        }
+        cookie?: never
+      }
+      requestBody?: never
+      responses: {
+        /** @description A focus session started on a task */
+        200: {
+          headers: {
+            [name: string]: unknown
+          }
+          content: {
+            'application/json': components['schemas']['FocusStart']
+          }
+        }
+        /** @description The task does not exist */
+        404: {
+          headers: {
+            [name: string]: unknown
+          }
+          content: {
+            'text/plain; charset=utf-8': unknown
+          }
+        }
+      }
+    }
+    delete?: never
+    options?: never
+    head?: never
+    patch?: never
+    trace?: never
+  }
+  '/api/tasks/{id}/focus/stop': {
+    parameters: {
+      query?: never
+      header?: never
+      path?: never
+      cookie?: never
+    }
+    get?: never
+    put?: never
+    /** End or pause a focus session: its time is added to the task */
+    post: {
+      parameters: {
+        query?: never
+        header?: never
+        path: {
+          id: number
+        }
+        cookie?: never
+      }
+      /** @description End (or pause) of a focus session */
+      requestBody: {
+        content: {
+          'application/json': components['schemas']['FocusStopBody']
+        }
+      }
+      responses: {
+        /** @description End of a focus session */
+        200: {
+          headers: {
+            [name: string]: unknown
+          }
+          content: {
+            'application/json': components['schemas']['FocusStop']
+          }
+        }
+        /** @description The session is too long */
+        400: {
+          headers: {
+            [name: string]: unknown
+          }
+          content: {
+            'text/plain; charset=utf-8': unknown
+          }
+        }
+        /** @description The task does not exist */
+        404: {
+          headers: {
+            [name: string]: unknown
+          }
+          content: {
+            'text/plain; charset=utf-8': unknown
+          }
+        }
+      }
+    }
+    delete?: never
+    options?: never
+    head?: never
+    patch?: never
+    trace?: never
+  }
   '/api/courses/{id}/files': {
     parameters: {
       query?: never
@@ -1064,6 +1226,7 @@ export interface components {
       course_code?: string | null
       /** Format: int32 */
       course_id: number
+      course_kind: components['schemas']['CourseKind']
       course_name: string
       /** Format: date-time */
       deadline: string
@@ -1076,32 +1239,45 @@ export interface components {
       /** Format: int32 */
       task_id: number
     }
+    /**
+     * @description A course, or an association: both have tasks, files and slots, only the courses have
+     *      teachers and grades.
+     */
     Course: {
-      /** @description e.g. "CS-477" */
+      /** @description e.g. "CS-477", or the acronym of an association */
       code?: string | null
+      /** @description Folder of its files in the storage, e.g. `Cours/CS-477 Advanced operating systems` */
+      folder: string
       /** Format: int32 */
       id: number
+      kind: components['schemas']['CourseKind']
       /** @description Main page of the course, usually on moodle */
       main_page_url?: string | null
       /** @description e.g. "Advanced operating systems" */
       name: string
       /** @description Weekly slots, sorted by weekday then start time */
       slots: components['schemas']['TimeSlot'][]
-      /** @description At least one */
+      /** @description At least one for a course, none for an association */
       teachers: string[]
     }
-    /** @description A course, without its slots: they are added and removed one by one */
+    /** @description A course or an association, without its slots: they are added and removed one by one */
     CourseBody: {
       code?: string | null
+      /** @description `course` by default. Cannot be changed once created. */
+      kind?: components['schemas']['CourseKind'] | null
       /** @description http(s) url of the main page of the course */
       main_page_url?: string | null
       name: string
-      /** @description At least one */
+      /**
+       * @description At least one for a course
+       * @default []
+       */
       teachers: string[]
     }
     /**
      * @description A file of a course: lecture notes written in the app, or (soon) an uploaded file.
-     *      Only the metadata is in the database, the content is in the storage (the NAS).
+     *      Only the metadata is in the database, the content is in the storage (the NAS), in the
+     *      folder of the course.
      */
     CourseFile: {
       /** Format: int32 */
@@ -1115,6 +1291,8 @@ export interface components {
       kind: components['schemas']['FileKind']
       /** @description For a note, e.g. "Lecture 2 Notes: Memory subsystem", the subtitle of its pdf */
       name: string
+      /** @description Path in the folder of the course, without extension, e.g. `Notes/Lecture 1 Notes` */
+      path: string
       /** @description e.g. slides, notes */
       tag_ids: number[]
       /** Format: date-time */
@@ -1134,10 +1312,20 @@ export interface components {
        */
       total_weight: number
     }
+    /** @enum {string} */
+    CourseKind: 'course' | 'association'
     CoursePath: {
       /** Format: int32 */
       id: number
     }
+    /** @description What a task needs to show of its course */
+    CourseSummary: {
+      code?: string | null
+      /** Format: int32 */
+      id: number
+      kind: components['schemas']['CourseKind']
+      name: string
+    }
     /** @description Every task of a course */
     CourseTasks: {
       /**
@@ -1170,6 +1358,49 @@ export interface components {
       tag_ids: number[]
     }
     FileKind: 'note' | 'upload'
+    /** @description A focus session started on a task */
+    FocusStart: {
+      course: components['schemas']['CourseSummary']
+      name: string
+      /** @description Name of the parent task, for a subtask */
+      parent_name?: string | null
+      /** Format: date-time */
+      started_at: string
+      /** @description Tags of the task, or of its parent for a subtask without any */
+      tag_ids: number[]
+      /** Format: int32 */
+      task_id: number
+      /**
+       * Format: int32
+       * @description Seconds already spent on the task before this session
+       */
+      time_spent: number
+      /** @description The running record, `None` when TimeTagger is not configured or failed */
+      timetagger?: components['schemas']['TimetaggerRecord'] | null
+      /** @description Whether TimeTagger is configured */
+      timetagger_enabled: boolean
+      /** @description Why TimeTagger failed, the session runs anyway */
+      timetagger_error?: string | null
+    }
+    /** @description End of a focus session */
+    FocusStop: {
+      /**
+       * Format: int32
+       * @description Seconds spent on the task, this session included
+       */
+      time_spent: number
+      timetagger_error?: string | null
+    }
+    /** @description End (or pause) of a focus session */
+    FocusStopBody: {
+      /**
+       * Format: uint32
+       * @description Length of the session, at most 24 hours
+       */
+      seconds: number
+      /** @description Record returned when the session started, to stop it */
+      timetagger?: components['schemas']['TimetaggerRecord'] | null
+    }
     /** @description A grade on any scale: `score` out of `max_score` */
     Grade: {
       /** Format: int32 */
@@ -1234,6 +1465,8 @@ export interface components {
       kind: components['schemas']['FileKind']
       /** @description For a note, e.g. "Lecture 2 Notes: Memory subsystem", the subtitle of its pdf */
       name: string
+      /** @description Path in the folder of the course, without extension, e.g. `Notes/Lecture 1 Notes` */
+      path: string
       /** @description e.g. slides, notes */
       tag_ids: number[]
       /** Format: date-time */
@@ -1279,6 +1512,8 @@ export interface components {
       name: components['schemas']['LocalizedString']
       /** @description What the tag can label */
       scopes: components['schemas']['TagScope'][]
+      /** @description Stable name, e.g. `homework` */
+      slug?: string | null
     }
     /** @enum {string} */
     TagScope: 'slot' | 'task' | 'file'
@@ -1307,6 +1542,11 @@ export interface components {
       /** @description Sorted like the tasks. Always empty for a subtask: there is only one level. */
       subtasks: components['schemas']['Task'][]
       tag_ids: number[]
+      /**
+       * Format: int32
+       * @description Seconds spent working on it, counted by the pomodoro
+       */
+      time_spent: number
     }
     TaskBody: {
       description?: string | null
@@ -1362,6 +1602,26 @@ export interface components {
        */
       weekday: number
     }
+    /**
+     * @description Record of TimeTagger (https://timetagger.app) counting a focus session. Kept by the
+     *      client while the session runs, and sent back to stop it.
+     */
+    TimetaggerRecord: {
+      /** @description Description holding the tags, e.g. `#cs-477 #homework #exercise-set-3` */
+      ds: string
+      key: string
+      /**
+       * Format: int64
+       * @description Start, unix timestamp in seconds
+       */
+      t1: number
+    }
+    /** @description A task not done yet, with its course, for the list of the things to do */
+    TodoTask: {
+      course: components['schemas']['CourseSummary']
+      /** @description With all its subtasks, the ones done included */
+      task: components['schemas']['Task']
+    }
   }
   responses: never
   parameters: never
diff --git a/frontend/src/locales/en.yml b/frontend/src/locales/en.yml
index c5762e1..263aec5 100644
--- a/frontend/src/locales/en.yml
+++ b/frontend/src/locales/en.yml
@@ -7,6 +7,7 @@ nav:
   home: Home
   schedule: Timetable
   courses: Courses
+  associations: Associations
   pomodoro: Pomodoro
   calendar: Calendar
   settings: Settings
@@ -16,7 +17,8 @@ home:
   sections:
     schedule: Check your weekly timetable.
     courses: Find your courses and their resources.
-    pomodoro: Work in focused sessions with regular breaks.
+    associations: Follow the tasks and meetings of your associations.
+    pomodoro: Focus on a task, the time is counted for you.
     calendar: Keep an eye on your exams and deadlines.
 theme:
   dark: Switch to dark mode
@@ -47,7 +49,7 @@ courses:
   save-error: Unable to save the course
   delete-error: Unable to delete the course
   delete-title: Do you really want to delete “{name}”?
-  delete-description: The course and all its slots will be permanently deleted.
+  delete-description: The course, its slots, tasks and files will be permanently deleted.
   form:
     description: Slots are then added from the timetable.
     name: Name
@@ -68,9 +70,38 @@ courses:
       teachers: Add at least one teacher.
       main-page: The address must start with http:// or https://.
       slot-time: Each slot must start before it ends, between 8:00 and 19:00.
+associations:
+  new: New association
+  edit: Edit association
+  empty: No association yet.
+  empty-hint: Add your associations to follow their tasks and meetings.
+  load-error: Unable to load the associations.
+  created: Association created
+  updated: Association updated
+  deleted: Association deleted
+  save-error: Unable to save the association
+  delete-error: Unable to delete the association
+  delete-title: Do you really want to delete “{name}”?
+  delete-description: The association, its slots, tasks and files will be permanently deleted.
+  form:
+    description: Its meetings are then added from the Deadlines tab or the timetable.
+    name-placeholder: Cultural committee
+    code: Acronym
+    code-placeholder: CoCu
+    main-page-placeholder: https://…
+association:
+  back: Back to associations
+  not-found: This association does not exist.
+  tabs:
+    files: Notes
+    deadlines: Deadlines
+  deadlines:
+    hint: Click or drag on the week to add a weekly slot (meeting…).
+    weekend: 'This weekend:'
 course:
   back: Back to courses
   not-found: This course does not exist.
+  folder: Folder of the files on the NAS
   tabs:
     files: Lectures
     tasks: Deadlines
@@ -139,8 +170,11 @@ tasks:
   add-subtask: Add a subtask…
   delete-title: Do you really want to delete “{name}”?
   delete-description: Its subtasks will be deleted too.
+  time-spent: '{time} of work'
   form:
     description: Homework, an exam or anything else to do.
+    course: Course or association
+    course-placeholder: Choose…
     name: Name
     name-placeholder: Exercise set 3
     tags: Tags
@@ -193,7 +227,9 @@ notes:
     theorem: Theorem
     example: Example
 files:
-  title: Course files
+  title:
+    course: Course files
+    association: Notes and files
   description: Slides, lecture notes and documents, soon stored on your NAS.
   upload: Upload
   coming-soon: File uploads are coming soon.
@@ -205,17 +241,52 @@ files:
   delete-title: Do you really want to delete “{name}”?
   delete-description: The file will be permanently deleted.
 calendar:
-  tabs:
-    courses: Courses
-    associations: Associations
+  show: Show
+  nothing-shown: Turn on the courses or the associations to see their tasks.
   today: Today
   previous: Previous month
   next: Next month
+  this-week: This week
+  previous-week: Previous week
+  next-week: Next week
   more: '+{n} more'
   nothing: Nothing due that day.
+  add-that-day: Add
   load-error: Unable to load the deadlines.
-  associations:
-    title: Association tasks
-    coming-soon: The tasks of your associations will show up here. Associations are coming soon.
+  todo:
+    title: To do
+    empty: Nothing to do, enjoy!
+    late: Late
+    today: Today
+    week: This week
+    later: Later
+    undated: No deadline
+focus:
+  start: Work on it (pomodoro)
+  back: Back to the pomodoro
+  pick: What do you want to work on?
+  no-task: No task to do.
+  start-free: Free session
+  free: Free session
+  elapsed: Focus time
+  pause: Pause
+  resume: Resume
+  stop: Finish
+  paused: Paused for {time}
+  suggested-break: suggested break {time}
+  cycles: '{n} cycle of 25 min | {n} cycles of 25 min'
+  cycle-done: '{n} × 25 min of focus'
+  cycle-hint: Well done! Take a break when you reach a good stopping point.
+  total: '{time} in total on this task'
+  space-hint: Space to pause
+  stopped: Session finished · {time}
+  resources: Resources
+  no-resource: No notes or slides for this course.
+  open-tab: Open in a new tab
+  close-resource: Close
+  fullscreen: Full screen
+  exit-fullscreen: Exit full screen
+  error: Unable to reach the server, the session did not change
+  timetagger-error: TimeTagger could not be updated
 placeholder:
   coming-soon: This page is coming soon.
diff --git a/frontend/src/locales/fr.yml b/frontend/src/locales/fr.yml
index 21f99c7..6a9faa8 100644
--- a/frontend/src/locales/fr.yml
+++ b/frontend/src/locales/fr.yml
@@ -7,6 +7,7 @@ nav:
   home: Accueil
   schedule: Emploi du temps
   courses: Cours
+  associations: Associations
   pomodoro: Pomodoro
   calendar: Calendrier
   settings: Configuration
@@ -16,7 +17,8 @@ home:
   sections:
     schedule: Consulte ton emploi du temps de la semaine.
     courses: Retrouve tes cours et leurs ressources.
-    pomodoro: Travaille par sessions concentrées avec des pauses régulières.
+    associations: Suis les tâches et réunions de tes associations.
+    pomodoro: Concentre-toi sur une tâche, le temps est compté pour toi.
     calendar: Garde un œil sur tes examens et échéances.
 theme:
   dark: Passer en mode sombre
@@ -47,7 +49,7 @@ courses:
   save-error: Impossible d'enregistrer le cours
   delete-error: Impossible de supprimer le cours
   delete-title: Voulez-vous vraiment supprimer « {name} » ?
-  delete-description: Le cours et tous ses créneaux seront supprimés définitivement.
+  delete-description: Le cours, ses créneaux, ses tâches et ses fichiers seront supprimés définitivement.
   form:
     description: Les créneaux s'ajoutent ensuite depuis l'emploi du temps.
     name: Nom
@@ -68,9 +70,38 @@ courses:
       teachers: Ajoute au moins un·e enseignant·e.
       main-page: L'adresse doit commencer par http:// ou https://.
       slot-time: Chaque créneau doit commencer avant de finir, entre 8h et 19h.
+associations:
+  new: Nouvelle association
+  edit: Modifier l'association
+  empty: Aucune association pour le moment.
+  empty-hint: Ajoute tes associations pour suivre leurs tâches et réunions.
+  load-error: Impossible de charger les associations.
+  created: Association créée
+  updated: Association modifiée
+  deleted: Association supprimée
+  save-error: Impossible d'enregistrer l'association
+  delete-error: Impossible de supprimer l'association
+  delete-title: Voulez-vous vraiment supprimer « {name} » ?
+  delete-description: L'association, ses créneaux, ses tâches et ses fichiers seront supprimés définitivement.
+  form:
+    description: Ses réunions s'ajoutent ensuite depuis l'onglet Échéances ou l'emploi du temps.
+    name-placeholder: Commission culturelle
+    code: Acronyme
+    code-placeholder: CoCu
+    main-page-placeholder: https://…
+association:
+  back: Retour aux associations
+  not-found: Cette association n'existe pas.
+  tabs:
+    files: Notes
+    deadlines: Échéances
+  deadlines:
+    hint: Clique ou glisse sur la semaine pour ajouter un créneau récurrent (réunion…).
+    weekend: 'Ce week-end :'
 course:
   back: Retour aux cours
   not-found: Ce cours n'existe pas.
+  folder: Dossier des fichiers sur le NAS
   tabs:
     files: Cours
     tasks: Échéances
@@ -139,8 +170,11 @@ tasks:
   add-subtask: Ajouter une sous-tâche…
   delete-title: Voulez-vous vraiment supprimer « {name} » ?
   delete-description: Ses sous-tâches seront aussi supprimées.
+  time-spent: '{time} de travail'
   form:
     description: Un devoir, un examen ou toute autre chose à faire.
+    course: Cours ou association
+    course-placeholder: Choisis…
     name: Nom
     name-placeholder: Série 3
     tags: Étiquettes
@@ -193,7 +227,9 @@ notes:
     theorem: Théorème
     example: Exemple
 files:
-  title: Fichiers du cours
+  title:
+    course: Fichiers du cours
+    association: Notes et fichiers
   description: Slides, notes de cours et documents, bientôt stockés sur ton NAS.
   upload: Importer
   coming-soon: L'import de fichiers arrive bientôt.
@@ -205,17 +241,52 @@ files:
   delete-title: Voulez-vous vraiment supprimer « {name} » ?
   delete-description: Le fichier sera supprimé définitivement.
 calendar:
-  tabs:
-    courses: Cours
-    associations: Associatif
+  show: Afficher
+  nothing-shown: Active les cours ou les associations pour voir leurs tâches.
   today: Aujourd'hui
   previous: Mois précédent
   next: Mois suivant
+  this-week: Cette semaine
+  previous-week: Semaine précédente
+  next-week: Semaine suivante
   more: '+{n} autre | +{n} autres'
   nothing: Rien à rendre ce jour-là.
+  add-that-day: Ajouter
   load-error: Impossible de charger les échéances.
-  associations:
-    title: Tâches associatives
-    coming-soon: Les tâches de tes associations apparaîtront ici. Les associations arrivent bientôt.
+  todo:
+    title: À faire
+    empty: Rien à faire, profite !
+    late: En retard
+    today: Aujourd'hui
+    week: Cette semaine
+    later: Plus tard
+    undated: Sans échéance
+focus:
+  start: Travailler dessus (pomodoro)
+  back: Revenir au pomodoro
+  pick: Sur quoi veux-tu travailler ?
+  no-task: Aucune tâche à faire.
+  start-free: Séance libre
+  free: Séance libre
+  elapsed: Temps de concentration
+  pause: Pause
+  resume: Reprendre
+  stop: Terminer
+  paused: En pause depuis {time}
+  suggested-break: pause conseillée {time}
+  cycles: '{n} cycle de 25 min | {n} cycles de 25 min'
+  cycle-done: '{n} × 25 min de concentration'
+  cycle-hint: Bravo ! Fais une pause quand tu arrives à un bon moment.
+  total: '{time} au total sur cette tâche'
+  space-hint: Espace pour mettre en pause
+  stopped: Séance terminée · {time}
+  resources: Ressources
+  no-resource: Aucune note ni slide pour ce cours.
+  open-tab: Ouvrir dans un nouvel onglet
+  close-resource: Fermer
+  fullscreen: Plein écran
+  exit-fullscreen: Quitter le plein écran
+  error: Impossible de joindre le serveur, la séance n'a pas changé
+  timetagger-error: TimeTagger n'a pas pu être mis à jour
 placeholder:
   coming-soon: Cette page arrive bientôt.
diff --git a/frontend/src/router/index.ts b/frontend/src/router/index.ts
index 26e1c50..af7e82f 100644
--- a/frontend/src/router/index.ts
+++ b/frontend/src/router/index.ts
@@ -1,4 +1,4 @@
-import { createRouter, createWebHistory } from 'vue-router'
+import { createRouter, createWebHistory, type RouteLocationNormalized } from 'vue-router'
 
 import HomeView from '@/views/HomeView.vue'
 
@@ -21,30 +21,37 @@ const router = createRouter({
       component: () => import('@/views/ScheduleView.vue'),
       meta: { title: 'nav.schedule' },
     },
-    {
-      name: 'courses',
-      path: '/courses',
-      component: () => import('@/views/CoursesView.vue'),
-      meta: { title: 'nav.courses' },
-    },
-    {
-      name: 'course',
-      path: '/courses/:id(\\d+)',
-      component: () => import('@/views/CourseView.vue'),
-      props: (route) => ({ id: Number(route.params.id) }),
-      meta: { title: 'nav.courses', section: 'courses' },
-    },
-    {
-      name: 'course-note',
-      // `new` to write a new note
-      path: '/courses/:id(\\d+)/notes/:noteId(\\d+|new)',
-      component: () => import('@/views/LectureNoteView.vue'),
-      props: (route) => ({
-        id: Number(route.params.id),
-        noteId: route.params.noteId === 'new' ? undefined : Number(route.params.noteId),
-      }),
-      meta: { title: 'nav.courses', section: 'courses' },
-    },
+    // The associations share the pages of the courses: see `utils/routes.ts`
+    ...(['course', 'association'] as const).flatMap((kind) => {
+      const list = `${kind}s`
+      return [
+        {
+          name: list,
+          path: `/${list}`,
+          component: () => import('@/views/CoursesView.vue'),
+          props: { kind },
+          meta: { title: `nav.${list}` },
+        },
+        {
+          name: kind,
+          path: `/${list}/:id(\\d+)`,
+          component: () => import('@/views/CourseView.vue'),
+          props: (route: RouteLocationNormalized) => ({ id: Number(route.params.id) }),
+          meta: { title: `nav.${list}`, section: list },
+        },
+        {
+          name: `${kind}-note`,
+          // `new` to write a new note
+          path: `/${list}/:id(\\d+)/notes/:noteId(\\d+|new)`,
+          component: () => import('@/views/LectureNoteView.vue'),
+          props: (route: RouteLocationNormalized) => ({
+            id: Number(route.params.id),
+            noteId: route.params.noteId === 'new' ? undefined : Number(route.params.noteId),
+          }),
+          meta: { title: `nav.${list}`, section: list },
+        },
+      ]
+    }),
     {
       name: 'pomodoro',
       path: '/pomodoro',
diff --git a/frontend/src/router/navigation.ts b/frontend/src/router/navigation.ts
index 9e9fb86..7204a6d 100644
--- a/frontend/src/router/navigation.ts
+++ b/frontend/src/router/navigation.ts
@@ -1,5 +1,5 @@
 import type { Component } from 'vue'
-import { BookOpen, CalendarClock, CalendarDays, Timer } from '@lucide/vue'
+import { BookOpen, CalendarClock, CalendarDays, Timer, Users } from '@lucide/vue'
 
 export interface NavigationEntry {
   /** Route name, see `router/index.ts` */
@@ -21,6 +21,12 @@ export const sections: NavigationEntry[] = [
     icon: CalendarClock,
   },
   { name: 'courses', title: 'nav.courses', description: 'home.sections.courses', icon: BookOpen },
+  {
+    name: 'associations',
+    title: 'nav.associations',
+    description: 'home.sections.associations',
+    icon: Users,
+  },
   { name: 'pomodoro', title: 'nav.pomodoro', description: 'home.sections.pomodoro', icon: Timer },
   {
     name: 'calendar',
diff --git a/frontend/src/services/api/course-files.ts b/frontend/src/services/api/course-files.ts
index a6b8a98..846ad86 100644
--- a/frontend/src/services/api/course-files.ts
+++ b/frontend/src/services/api/course-files.ts
@@ -5,7 +5,7 @@ import { toValue, type MaybeRefOrGetter } from 'vue'
 import type { CourseFile, LectureNoteBody } from '@/utils/types'
 import { getClient } from './client'
 
-function filesKey(courseId: MaybeRefOrGetter<number>) {
+function filesKey(courseId: MaybeRefOrGetter<number | undefined>) {
   return ['course', courseId, 'files']
 }
 
@@ -22,13 +22,14 @@ export function lectureNotePdfUrl(note: CourseFile) {
   return `/api/notes/${note.id}/pdf?v=${encodeURIComponent(note.updated_at)}`
 }
 
-/** Files of a course (lecture notes...), without their content */
-export function useCourseFiles(courseId: MaybeRefOrGetter<number>) {
+/** Files of a course (lecture notes...), without their content. Disabled without course. */
+export function useCourseFiles(courseId: MaybeRefOrGetter<number | undefined>) {
   return useQuery({
     queryKey: filesKey(courseId),
+    enabled: () => toValue(courseId) !== undefined,
     queryFn: async () => {
       const { data, response } = await getClient().GET('/api/courses/{id}/files', {
-        params: { path: { id: toValue(courseId) } },
+        params: { path: { id: toValue(courseId)! } },
       })
       return response.status === HttpStatus.OK && data ? data : unexpected(response.status)
     },
diff --git a/frontend/src/services/api/courses.ts b/frontend/src/services/api/courses.ts
index 61e55e7..452a05c 100644
--- a/frontend/src/services/api/courses.ts
+++ b/frontend/src/services/api/courses.ts
@@ -1,8 +1,8 @@
 import { useMutation, useQuery, useQueryClient, type QueryClient } from '@tanstack/vue-query'
 import { HttpStatus } from 'http-status-ts'
-import { toValue, type MaybeRefOrGetter } from 'vue'
+import { computed, toValue, type MaybeRefOrGetter } from 'vue'
 
-import type { Course, CourseBody, TimeSlotBody } from '@/utils/types'
+import type { Course, CourseBody, CourseKind, TimeSlotBody } from '@/utils/types'
 import { getClient } from './client'
 
 const COURSES_KEY = ['courses']
@@ -23,6 +23,7 @@ function storeCourse(queryClient: QueryClient, course: Course) {
   queryClient.setQueryData(courseKey(course.id), course)
 }
 
+/** Every course and association, sorted by name */
 export function useCourses() {
   return useQuery({
     queryKey: COURSES_KEY,
@@ -36,6 +37,13 @@ export function useCourses() {
   })
 }
 
+/** Only the courses, or only the associations */
+export function useCoursesOfKind(kind: MaybeRefOrGetter<CourseKind>) {
+  const query = useCourses()
+  const data = computed(() => query.data.value?.filter((c) => c.kind === toValue(kind)))
+  return { ...query, data }
+}
+
 export function useCourse(id: MaybeRefOrGetter<number>) {
   const queryClient = useQueryClient()
   return useQuery({
diff --git a/frontend/src/services/api/tasks.ts b/frontend/src/services/api/tasks.ts
index f8b7c6e..7abd992 100644
--- a/frontend/src/services/api/tasks.ts
+++ b/frontend/src/services/api/tasks.ts
@@ -2,7 +2,15 @@ import { useMutation, useQuery, useQueryClient } from '@tanstack/vue-query'
 import { HttpStatus } from 'http-status-ts'
 import { toValue, type MaybeRefOrGetter } from 'vue'
 
-import type { CourseTasks, CreateTaskBody, Task, TaskBody } from '@/utils/types'
+import type {
+  CourseTasks,
+  CreateTaskBody,
+  FocusStart,
+  FocusStop,
+  Task,
+  TaskBody,
+  TimetaggerRecord,
+} from '@/utils/types'
 import { getClient } from './client'
 
 // Every mutation answers with all the tasks of the course (nested, sorted) and the
@@ -12,6 +20,8 @@ function tasksKey(courseId: MaybeRefOrGetter<number>) {
   return ['course', courseId, 'tasks']
 }
 
+const TODO_KEY = ['todo-tasks']
+
 function unexpected(status: number): never {
   throw new Error(`Unexpected status code received: ${status}`)
 }
@@ -57,18 +67,34 @@ export function useCalendarTasks(period: MaybeRefOrGetter<{ from: string; to: st
   })
 }
 
-export function useTaskMutations(courseId: MaybeRefOrGetter<number>) {
+/** Tasks not done of every course and association, the closest deadline first */
+export function useTodoTasks() {
+  return useQuery({
+    queryKey: TODO_KEY,
+    queryFn: async () => {
+      const { data, response } = await getClient().GET('/api/tasks/todo')
+      return response.status === HttpStatus.OK && data ? data : unexpected(response.status)
+    },
+  })
+}
+
+/**
+ * Mutations of the tasks of any course: the course is given with each call. See
+ * `useTaskMutations` for the tasks of a single course.
+ */
+export function useAnyTaskMutations() {
   const queryClient = useQueryClient()
-  const onSuccess = (tasks: CourseTasks) => {
-    queryClient.setQueryData(tasksKey(toValue(courseId)), tasks)
-    // Refetched when the calendar is shown again
+  const onSuccess = (tasks: CourseTasks, { courseId }: { courseId: number }) => {
+    queryClient.setQueryData(tasksKey(courseId), tasks)
+    // Refetched when they are shown again
     queryClient.invalidateQueries({ queryKey: ['calendar-tasks'] })
+    queryClient.invalidateQueries({ queryKey: TODO_KEY })
   }
 
   const create = useMutation({
-    mutationFn: async (body: CreateTaskBody) => {
+    mutationFn: async ({ courseId, body }: { courseId: number; body: CreateTaskBody }) => {
       const { data, response } = await getClient().POST('/api/courses/{id}/tasks', {
-        params: { path: { id: toValue(courseId) } },
+        params: { path: { id: courseId } },
         body,
       })
       return response.status === HttpStatus.OK && data ? data : unexpected(response.status)
@@ -77,7 +103,7 @@ export function useTaskMutations(courseId: MaybeRefOrGetter<number>) {
   })
 
   const update = useMutation({
-    mutationFn: async ({ id, body }: { id: number; body: TaskBody }) => {
+    mutationFn: async ({ id, body }: { courseId: number; id: number; body: TaskBody }) => {
       const { data, response } = await getClient().PUT('/api/tasks/{id}', {
         params: { path: { id } },
         body,
@@ -88,7 +114,7 @@ export function useTaskMutations(courseId: MaybeRefOrGetter<number>) {
   })
 
   const remove = useMutation({
-    mutationFn: async (id: number) => {
+    mutationFn: async ({ id }: { courseId: number; id: number }) => {
       const { data, response } = await getClient().DELETE('/api/tasks/{id}', {
         params: { path: { id } },
       })
@@ -99,3 +125,54 @@ export function useTaskMutations(courseId: MaybeRefOrGetter<number>) {
 
   return { create, update, remove }
 }
+
+/** Mutations of the tasks of a single course */
+export function useTaskMutations(courseId: MaybeRefOrGetter<number>) {
+  const { create, update, remove } = useAnyTaskMutations()
+  return {
+    create: {
+      ...create,
+      mutateAsync: (body: CreateTaskBody) =>
+        create.mutateAsync({ courseId: toValue(courseId), body }),
+    },
+    update: {
+      ...update,
+      mutateAsync: ({ id, body }: { id: number; body: TaskBody }) =>
+        update.mutateAsync({ courseId: toValue(courseId), id, body }),
+    },
+    remove: {
+      ...remove,
+      mutateAsync: (id: number) => remove.mutateAsync({ courseId: toValue(courseId), id }),
+    },
+  }
+}
+
+/** Starts a focus session on a task, and its TimeTagger record */
+export async function startFocus(taskId: number): Promise<FocusStart> {
+  const { data, response } = await getClient().POST('/api/tasks/{id}/focus', {
+    params: { path: { id: taskId } },
+  })
+  return response.status === HttpStatus.OK && data ? data : unexpected(response.status)
+}
+
+/** Ends (or pauses) a focus session: its time is added to the task */
+export async function stopFocus(
+  taskId: number,
+  seconds: number,
+  timetagger: TimetaggerRecord | null,
+): Promise<FocusStop> {
+  const { data, response } = await getClient().POST('/api/tasks/{id}/focus/stop', {
+    params: { path: { id: taskId } },
+    body: { seconds, timetagger },
+  })
+  return response.status === HttpStatus.OK && data ? data : unexpected(response.status)
+}
+
+/** The time spent on the tasks changed: shown again from the server */
+export function useRefreshTasks() {
+  const queryClient = useQueryClient()
+  return (courseId: number) => {
+    queryClient.invalidateQueries({ queryKey: tasksKey(courseId) })
+    queryClient.invalidateQueries({ queryKey: TODO_KEY })
+  }
+}
diff --git a/frontend/src/services/focus.ts b/frontend/src/services/focus.ts
new file mode 100644
index 0000000..ba9baff
--- /dev/null
+++ b/frontend/src/services/focus.ts
@@ -0,0 +1,204 @@
+/**
+ * Focus session of the pomodoro, shared by every page and kept across reloads. The
+ * pomodoro counts up: the session runs until it is paused or stopped.
+ *
+ * On a task, every run (from a start or a resume to a pause or a stop) is sent to the
+ * backend, which adds its time to the task and counts it in TimeTagger. A free session,
+ * without task, stays in the browser.
+ */
+import { computed, ref, watch } from 'vue'
+
+import { startFocus, stopFocus } from '@/services/api/tasks'
+import type { FocusStart, TimetaggerRecord } from '@/utils/types'
+
+/** One cycle of the classic pomodoro, in seconds: a break is suggested after each */
+export const CYCLE_SECONDS = 25 * 60
+
+export interface FocusSession {
+  /** The task, `null` for a free session */
+  task: FocusStart | null
+  /** Seconds of the runs before the current one */
+  accumulated: number
+  /** Start of the current run (ms), `null` while paused */
+  runningSince: number | null
+  /** Start of the pause (ms), `null` while running */
+  pausedAt: number | null
+  /** TimeTagger record of the current run */
+  record: TimetaggerRecord | null
+  /** Seconds spent on the task before the session */
+  spentBefore: number
+}
+
+const STORAGE_KEY = 'focus-session'
+
+function load(): FocusSession | null {
+  try {
+    const raw = window.localStorage.getItem(STORAGE_KEY)
+    return raw ? (JSON.parse(raw) as FocusSession) : null
+  } catch {
+    return null
+  }
+}
+
+const session = ref<FocusSession | null>(load())
+
+watch(
+  session,
+  (value) => {
+    try {
+      if (value) window.localStorage.setItem(STORAGE_KEY, JSON.stringify(value))
+      else window.localStorage.removeItem(STORAGE_KEY)
+    } catch {
+      // Private browsing: the session is only lost on reload
+    }
+  },
+  { deep: true },
+)
+
+/** Current time, refreshed every second */
+const now = ref(Date.now())
+window.setInterval(() => (now.value = Date.now()), 1000)
+
+/** Seconds of the current run */
+function runSeconds(value: FocusSession, at = now.value) {
+  return value.runningSince === null ? 0 : Math.max(0, Math.round((at - value.runningSince) / 1000))
+}
+
+/** Seconds of focus of the session */
+const elapsed = computed(() =>
+  session.value ? session.value.accumulated + runSeconds(session.value) : 0,
+)
+/** Seconds of the current pause */
+const pauseElapsed = computed(() =>
+  session.value?.pausedAt
+    ? Math.max(0, Math.round((now.value - session.value.pausedAt) / 1000))
+    : 0,
+)
+const isRunning = computed(() => session.value?.runningSince != null)
+
+/** Busy talking to the backend */
+const pending = ref(false)
+
+async function withPending<T>(action: () => Promise<T>): Promise<T> {
+  pending.value = true
+  try {
+    return await action()
+  } finally {
+    pending.value = false
+  }
+}
+
+/** Sends a run of `seconds` to the backend. Returns the TimeTagger error, if any. */
+async function endRun(value: FocusSession, seconds: number): Promise<string | null> {
+  if (!value.task) return null
+  const result = await stopFocus(value.task.task_id, seconds, value.record)
+  return result.timetagger_error ?? null
+}
+
+/**
+ * Starts a session on a task (`null`: a free session), ending the running one. Returns
+ * the TimeTagger error, if any: the session runs anyway.
+ */
+async function start(taskId: number | null): Promise<string | null> {
+  return withPending(async () => {
+    if (session.value) await stopNow()
+    if (taskId === null) {
+      session.value = {
+        task: null,
+        accumulated: 0,
+        runningSince: Date.now(),
+        pausedAt: null,
+        record: null,
+        spentBefore: 0,
+      }
+      return null
+    }
+    const task = await startFocus(taskId)
+    session.value = {
+      task,
+      accumulated: 0,
+      runningSince: new Date(task.started_at).getTime(),
+      pausedAt: null,
+      record: task.timetagger ?? null,
+      spentBefore: task.time_spent,
+    }
+    return task.timetagger_error ?? null
+  })
+}
+
+async function pause(): Promise<string | null> {
+  const value = session.value
+  if (!value || value.runningSince === null) return null
+  return withPending(async () => {
+    const seconds = runSeconds(value, Date.now())
+    const error = await endRun(value, seconds)
+    value.accumulated += seconds
+    value.runningSince = null
+    value.pausedAt = Date.now()
+    value.record = null
+    return error
+  })
+}
+
+async function resume(): Promise<string | null> {
+  const value = session.value
+  if (!value || value.runningSince !== null) return null
+  return withPending(async () => {
+    let error: string | null = null
+    if (value.task) {
+      const task = await startFocus(value.task.task_id)
+      value.task = task
+      value.record = task.timetagger ?? null
+      error = task.timetagger_error ?? null
+    }
+    value.runningSince = Date.now()
+    value.pausedAt = null
+    return error
+  })
+}
+
+async function stopNow(): Promise<string | null> {
+  const value = session.value
+  if (!value) return null
+  const error =
+    value.runningSince === null ? null : await endRun(value, runSeconds(value, Date.now()))
+  session.value = null
+  return error
+}
+
+/** Ends the session. Returns the TimeTagger error, if any. */
+async function stop(): Promise<string | null> {
+  return withPending(stopNow)
+}
+
+export function useFocus() {
+  return {
+    session,
+    elapsed,
+    pauseElapsed,
+    isRunning,
+    pending,
+    now,
+    start,
+    pause,
+    resume,
+    stop,
+  }
+}
+
+/** 3725 -> "1:02:05", 125 -> "02:05" */
+export function formatDuration(seconds: number): string {
+  const pad = (n: number) => String(n).padStart(2, '0')
+  const hours = Math.floor(seconds / 3600)
+  const minutes = Math.floor((seconds % 3600) / 60)
+  const rest = seconds % 60
+  return hours ? `${hours}:${pad(minutes)}:${pad(rest)}` : `${pad(minutes)}:${pad(rest)}`
+}
+
+/** 5400 -> "1 h 30", 600 -> "10 min" */
+export function formatSpent(seconds: number): string {
+  const hours = Math.floor(seconds / 3600)
+  const minutes = Math.floor((seconds % 3600) / 60)
+  if (!hours) return `${minutes} min`
+  return `${hours} h ${String(minutes).padStart(2, '0')}`
+}
diff --git a/frontend/src/utils/calendar.ts b/frontend/src/utils/calendar.ts
index e820e03..c53e93a 100644
--- a/frontend/src/utils/calendar.ts
+++ b/frontend/src/utils/calendar.ts
@@ -7,7 +7,7 @@ export function dayKey(date: Date): string {
 }
 
 /** Monday of the week of `date`, at midnight */
-function startOfWeek(date: Date): Date {
+export function startOfWeek(date: Date): Date {
   const day = new Date(date.getFullYear(), date.getMonth(), date.getDate())
   const offset = (day.getDay() + 6) % 7
   day.setDate(day.getDate() - offset)
diff --git a/frontend/src/utils/routes.ts b/frontend/src/utils/routes.ts
new file mode 100644
index 0000000..9ab25c6
--- /dev/null
+++ b/frontend/src/utils/routes.ts
@@ -0,0 +1,43 @@
+/** Routes of the courses and the associations, which share their pages */
+import type { RouteLocationRaw } from 'vue-router'
+
+import type { CourseKind } from '@/utils/types'
+
+const NAMES = {
+  course: { list: 'courses', page: 'course', note: 'course-note' },
+  association: { list: 'associations', page: 'association', note: 'association-note' },
+} as const
+
+export function listRoute(kind: CourseKind): RouteLocationRaw {
+  return { name: NAMES[kind].list }
+}
+
+export function coursePageRoute(
+  course: { id: number; kind: CourseKind },
+  tab?: string,
+): RouteLocationRaw {
+  return { name: NAMES[course.kind].page, params: { id: course.id }, query: tab ? { tab } : {} }
+}
+
+/** `noteId` 'new' to write a new note */
+export function noteRoute(
+  course: { id: number; kind: CourseKind },
+  noteId: number | 'new',
+  edit = false,
+): RouteLocationRaw {
+  return {
+    name: NAMES[course.kind].note,
+    params: { id: course.id, noteId },
+    query: edit ? { edit: '1' } : {},
+  }
+}
+
+/** Tab listing the tasks, which differs between courses and associations */
+export function tasksTab(kind: CourseKind) {
+  return kind === 'course' ? 'tasks' : 'deadlines'
+}
+
+/** Starts the pomodoro on a task */
+export function focusRoute(taskId: number): RouteLocationRaw {
+  return { name: 'pomodoro', query: { task: taskId } }
+}
diff --git a/frontend/src/utils/types.ts b/frontend/src/utils/types.ts
index 42b9908..bcabfe8 100644
--- a/frontend/src/utils/types.ts
+++ b/frontend/src/utils/types.ts
@@ -5,6 +5,8 @@ type Schemas = components['schemas']
 
 export type LocalizedString = Schemas['LocalizedString']
 export type Course = Schemas['Course']
+export type CourseKind = Schemas['CourseKind']
+export type CourseSummary = Schemas['CourseSummary']
 export type CourseBody = Schemas['CourseBody']
 export type TimeSlot = Schemas['TimeSlot']
 export type TimeSlotBody = Schemas['TimeSlotBody']
@@ -16,6 +18,10 @@ export type TaskBody = Schemas['TaskBody']
 export type CreateTaskBody = Schemas['CreateTaskBody']
 export type CourseTasks = Schemas['CourseTasks']
 export type CalendarTask = Schemas['CalendarTask']
+export type TodoTask = Schemas['TodoTask']
+export type FocusStart = Schemas['FocusStart']
+export type FocusStop = Schemas['FocusStop']
+export type TimetaggerRecord = Schemas['TimetaggerRecord']
 export type CourseFile = Schemas['CourseFile']
 export type TagScope = Schemas['TagScope']
 export type LectureNoteBody = Schemas['LectureNoteBody']
diff --git a/frontend/src/views/CalendarView.vue b/frontend/src/views/CalendarView.vue
index 9cc7163..3dd4eb2 100644
--- a/frontend/src/views/CalendarView.vue
+++ b/frontend/src/views/CalendarView.vue
@@ -1,41 +1,113 @@
 <script setup lang="ts">
-/** Deadlines of every course in a month calendar, and (soon) the ones of the associations */
-import { computed } from 'vue'
-import { useRoute, useRouter } from 'vue-router'
-import { Users } from '@lucide/vue'
+/**
+ * Deadlines of the courses and associations in a month calendar, next to everything left
+ * to do. Courses and associations can each be hidden, and tasks created from here.
+ */
+import { computed, ref, watch } from 'vue'
+import { BookOpen, Plus, Users } from '@lucide/vue'
 
-import CoursesCalendar from '@/components/calendar/CoursesCalendar.vue'
-import { Card, CardDescription, CardTitle } from '@/components/ui/card'
-import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
+import TasksCalendar from '@/components/calendar/TasksCalendar.vue'
+import TodoList from '@/components/calendar/TodoList.vue'
+import TaskFormDialog from '@/components/course/TaskFormDialog.vue'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import type { CourseKind } from '@/utils/types'
 
-const route = useRoute()
-const router = useRouter()
+const KINDS: { kind: CourseKind; icon: typeof BookOpen }[] = [
+  { kind: 'course', icon: BookOpen },
+  { kind: 'association', icon: Users },
+]
 
-const TABS = ['courses', 'associations'] as const
-type Tab = (typeof TABS)[number]
+// Remembered in the browser: only a convenience
+const STORAGE_KEY = 'calendar-kinds'
 
-const tab = computed<Tab>({
-  get: () => TABS.find((tab) => tab === route.query.tab) ?? 'courses',
-  set: (tab) => router.replace({ query: { ...route.query, tab } }),
+function loadKinds(): CourseKind[] {
+  try {
+    const saved = JSON.parse(window.localStorage.getItem(STORAGE_KEY) ?? 'null')
+    if (Array.isArray(saved)) return saved.filter((k) => k === 'course' || k === 'association')
+  } catch {
+    // Unavailable or invalid: everything is shown
+  }
+  return ['course', 'association']
+}
+
+const kinds = ref<CourseKind[]>(loadKinds())
+watch(kinds, (value) => {
+  try {
+    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(value))
+  } catch {
+    // Not remembered
+  }
 })
+
+function toggle(kind: CourseKind) {
+  kinds.value = kinds.value.includes(kind)
+    ? kinds.value.filter((k) => k !== kind)
+    : [...kinds.value, kind]
+}
+
+const formOpen = ref(false)
+const defaultDeadline = ref<string>()
+
+/** New task, due at the end of `day` when given */
+function openForm(day?: Date) {
+  if (day) {
+    const end = new Date(day)
+    end.setHours(23, 59, 0, 0)
+    defaultDeadline.value = end.toISOString()
+  } else {
+    defaultDeadline.value = undefined
+  }
+  formOpen.value = true
+}
+
+const nothingShown = computed(() => !kinds.value.length)
 </script>
 
 <template>
-  <Tabs v-model="tab" class="mx-auto max-w-6xl gap-4">
-    <TabsList>
-      <TabsTrigger v-for="name in TABS" :key="name" :value="name">
-        {{ $t(`calendar.tabs.${name}`) }}
-      </TabsTrigger>
-    </TabsList>
-    <TabsContent value="courses" class="min-w-0">
-      <CoursesCalendar />
-    </TabsContent>
-    <TabsContent value="associations">
-      <Card class="mx-auto flex max-w-md flex-col items-center gap-2 p-8 text-center">
-        <Users class="mb-2 size-8 text-muted-foreground" />
-        <CardTitle class="text-base">{{ $t('calendar.associations.title') }}</CardTitle>
-        <CardDescription>{{ $t('calendar.associations.coming-soon') }}</CardDescription>
+  <div class="mx-auto flex max-w-7xl flex-col gap-4">
+    <div class="flex flex-wrap items-center gap-2">
+      <div class="flex gap-2" role="group" :aria-label="$t('calendar.show')">
+        <button
+          v-for="{ kind, icon } in KINDS"
+          :key="kind"
+          type="button"
+          class="inline-flex items-center gap-2 rounded-full border px-3 py-1.5 text-sm transition-colors"
+          :class="
+            kinds.includes(kind)
+              ? 'border-primary bg-primary/10 font-medium text-primary'
+              : 'text-muted-foreground hover:bg-accent'
+          "
+          :aria-pressed="kinds.includes(kind)"
+          @click="toggle(kind)"
+        >
+          <component :is="icon" class="size-4" />
+          {{ $t(`nav.${kind}s`) }}
+        </button>
+      </div>
+      <Button class="ml-auto" @click="openForm()">
+        <Plus />
+        {{ $t('tasks.new') }}
+      </Button>
+    </div>
+
+    <p v-if="nothingShown" class="text-sm text-muted-foreground">
+      {{ $t('calendar.nothing-shown') }}
+    </p>
+
+    <div class="grid items-start gap-4 lg:grid-cols-[minmax(0,1fr)_22rem]">
+      <TasksCalendar :kinds="kinds" class="min-w-0" @create="openForm" />
+
+      <Card class="lg:sticky lg:top-4 lg:max-h-[calc(100svh-6rem)] lg:overflow-y-auto">
+        <CardHeader>
+          <CardTitle class="text-base">{{ $t('calendar.todo.title') }}</CardTitle>
+        </CardHeader>
+        <CardContent>
+          <TodoList :kinds="kinds" />
+        </CardContent>
       </Card>
-    </TabsContent>
-  </Tabs>
+    </div>
+
+    <TaskFormDialog v-model:open="formOpen" :default-deadline="defaultDeadline" />
+  </div>
 </template>
diff --git a/frontend/src/views/CourseView.vue b/frontend/src/views/CourseView.vue
index a7d3d3d..5b72e87 100644
--- a/frontend/src/views/CourseView.vue
+++ b/frontend/src/views/CourseView.vue
@@ -1,9 +1,13 @@
 <script setup lang="ts">
-/** Personal page of a course: its files, deadlines, timetable and grades */
-import { computed } from 'vue'
+/**
+ * Personal page of a course: its files, deadlines, timetable and grades. An association
+ * has its notes, and its deadlines on top of its timetable.
+ */
+import { computed, watch } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
-import { ArrowLeft, ExternalLink } from '@lucide/vue'
+import { ArrowLeft, ExternalLink, Folder } from '@lucide/vue'
 
+import AssociationDeadlinesTab from '@/components/course/AssociationDeadlinesTab.vue'
 import CourseFilesTab from '@/components/course/CourseFilesTab.vue'
 import CourseGradesTab from '@/components/course/CourseGradesTab.vue'
 import CourseScheduleTab from '@/components/course/CourseScheduleTab.vue'
@@ -14,6 +18,7 @@ import { Card, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
 import { Skeleton } from '@/components/ui/skeleton'
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
 import { useCourse } from '@/services/api/courses'
+import { coursePageRoute, listRoute } from '@/utils/routes'
 
 const props = defineProps<{ id: number }>()
 
@@ -21,22 +26,36 @@ const route = useRoute()
 const router = useRouter()
 const { data: course, isPending, isError, refetch } = useCourse(() => props.id)
 
-const TABS = ['files', 'tasks', 'schedule', 'grades'] as const
-type Tab = (typeof TABS)[number]
+/** Kind of the page, from the route: the course may not be loaded yet */
+const kind = computed(() => (route.name === 'association' ? 'association' : 'course'))
+const tabs = computed(() =>
+  kind.value === 'course' ? ['files', 'tasks', 'schedule', 'grades'] : ['files', 'deadlines'],
+)
 
 // In the url, so that coming back from a note opens the files again
-const tab = computed<Tab>({
-  get: () => TABS.find((tab) => tab === route.query.tab) ?? 'files',
+const tab = computed<string>({
+  get: () => tabs.value.find((tab) => tab === route.query.tab) ?? 'files',
   set: (tab) => router.replace({ query: { ...route.query, tab } }),
 })
+
+// A course opened as an association (or the other way round): to its own page
+watch(
+  () => course.value?.kind,
+  (courseKind) => {
+    if (courseKind && courseKind !== kind.value) {
+      router.replace(coursePageRoute(course.value!, route.query.tab as string | undefined))
+    }
+  },
+  { immediate: true },
+)
 </script>
 
 <template>
   <div class="mx-auto flex max-w-6xl flex-col gap-4">
     <Button variant="ghost" class="self-start" as-child>
-      <RouterLink :to="{ name: 'courses' }">
+      <RouterLink :to="listRoute(kind)">
         <ArrowLeft />
-        {{ $t('course.back') }}
+        {{ $t(`${kind}.back`) }}
       </RouterLink>
     </Button>
 
@@ -44,7 +63,7 @@ const tab = computed<Tab>({
 
     <Card v-else-if="isError || !course" class="mx-auto max-w-md text-center">
       <CardHeader>
-        <CardTitle>{{ $t('course.not-found') }}</CardTitle>
+        <CardTitle>{{ $t(`${kind}.not-found`) }}</CardTitle>
       </CardHeader>
       <CardFooter class="justify-center">
         <Button variant="outline" @click="refetch()">{{ $t('common.retry') }}</Button>
@@ -60,7 +79,16 @@ const tab = computed<Tab>({
               {{ course.code }}
             </Badge>
           </div>
-          <p class="text-sm text-muted-foreground">{{ course.teachers.join(', ') }}</p>
+          <p v-if="course.teachers.length" class="text-sm text-muted-foreground">
+            {{ course.teachers.join(', ') }}
+          </p>
+          <p
+            class="flex items-center gap-1.5 text-xs text-muted-foreground"
+            :title="$t('course.folder')"
+          >
+            <Folder class="size-3.5" />
+            <span class="font-mono">{{ course.folder }}</span>
+          </p>
         </div>
         <Button v-if="course.main_page_url" variant="outline" as-child>
           <a :href="course.main_page_url" target="_blank" rel="noopener noreferrer">
@@ -72,12 +100,15 @@ const tab = computed<Tab>({
 
       <Tabs v-model="tab" class="gap-4">
         <TabsList class="w-full justify-start overflow-x-auto sm:w-auto">
-          <TabsTrigger v-for="name in TABS" :key="name" :value="name">
-            {{ $t(`course.tabs.${name}`) }}
+          <TabsTrigger v-for="name in tabs" :key="name" :value="name">
+            {{ $t(`${kind}.tabs.${name}`) }}
           </TabsTrigger>
         </TabsList>
         <TabsContent value="files">
-          <CourseFilesTab :course-id="course.id" />
+          <CourseFilesTab :course="course" />
+        </TabsContent>
+        <TabsContent value="deadlines" class="min-w-0">
+          <AssociationDeadlinesTab :course="course" />
         </TabsContent>
         <TabsContent value="tasks">
           <CourseTasksTab :course-id="course.id" />
diff --git a/frontend/src/views/CoursesView.vue b/frontend/src/views/CoursesView.vue
index 219e670..fb7d913 100644
--- a/frontend/src/views/CoursesView.vue
+++ b/frontend/src/views/CoursesView.vue
@@ -1,8 +1,9 @@
 <script setup lang="ts">
-import { ref } from 'vue'
+/** List of the courses, or of the associations: both are managed the same way */
+import { computed, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { toast } from 'vue-sonner'
-import { BookOpen, Pencil, Plus, Trash2 } from '@lucide/vue'
+import { BookOpen, Pencil, Plus, Trash2, Users } from '@lucide/vue'
 
 import CourseFormDialog from '@/components/courses/CourseFormDialog.vue'
 import {
@@ -19,11 +20,17 @@ import { Badge } from '@/components/ui/badge'
 import { Button } from '@/components/ui/button'
 import { Card, CardDescription, CardFooter, CardHeader, CardTitle } from '@/components/ui/card'
 import { Skeleton } from '@/components/ui/skeleton'
-import { useCourses, useDeleteCourse } from '@/services/api/courses'
-import type { Course } from '@/utils/types'
+import { useCoursesOfKind, useDeleteCourse } from '@/services/api/courses'
+import { coursePageRoute } from '@/utils/routes'
+import type { Course, CourseKind } from '@/utils/types'
+
+const props = defineProps<{ kind: CourseKind }>()
 
 const { t } = useI18n()
-const { data: courses, isPending, isError, refetch } = useCourses()
+const { data: courses, isPending, isError, refetch } = useCoursesOfKind(() => props.kind)
+
+/** Prefix of the texts of the page */
+const k = computed(() => (props.kind === 'course' ? 'courses' : 'associations'))
 const deleteCourse = useDeleteCourse()
 
 const formOpen = ref(false)
@@ -46,9 +53,9 @@ async function confirmDelete() {
   if (!deletedCourse.value) return
   try {
     await deleteCourse.mutateAsync(deletedCourse.value.id)
-    toast.success(t('courses.deleted'))
+    toast.success(t(`${k.value}.deleted`))
   } catch {
-    toast.error(t('courses.delete-error'))
+    toast.error(t(`${k.value}.delete-error`))
   }
 }
 </script>
@@ -58,7 +65,7 @@ async function confirmDelete() {
     <div class="flex items-center justify-end">
       <Button @click="openForm()">
         <Plus />
-        {{ $t('courses.new') }}
+        {{ $t(`${k}.new`) }}
       </Button>
     </div>
 
@@ -68,7 +75,7 @@ async function confirmDelete() {
 
     <Card v-else-if="isError" class="mx-auto max-w-md text-center">
       <CardHeader>
-        <CardTitle>{{ $t('courses.load-error') }}</CardTitle>
+        <CardTitle>{{ $t(`${k}.load-error`) }}</CardTitle>
       </CardHeader>
       <CardFooter class="justify-center">
         <Button variant="outline" @click="refetch()">{{ $t('common.retry') }}</Button>
@@ -77,14 +84,17 @@ async function confirmDelete() {
 
     <Card v-else-if="!courses?.length" class="mx-auto max-w-md text-center">
       <CardHeader>
-        <BookOpen class="mx-auto mb-2 size-8 text-muted-foreground" />
-        <CardTitle>{{ $t('courses.empty') }}</CardTitle>
-        <CardDescription>{{ $t('courses.empty-hint') }}</CardDescription>
+        <component
+          :is="kind === 'course' ? BookOpen : Users"
+          class="mx-auto mb-2 size-8 text-muted-foreground"
+        />
+        <CardTitle>{{ $t(`${k}.empty`) }}</CardTitle>
+        <CardDescription>{{ $t(`${k}.empty-hint`) }}</CardDescription>
       </CardHeader>
       <CardFooter class="justify-center">
         <Button @click="openForm()">
           <Plus />
-          {{ $t('courses.new') }}
+          {{ $t(`${k}.new`) }}
         </Button>
       </CardFooter>
     </Card>
@@ -100,7 +110,7 @@ async function confirmDelete() {
           <div class="flex flex-wrap items-center gap-2">
             <CardTitle class="text-lg leading-snug">
               <RouterLink
-                :to="{ name: 'course', params: { id: course.id } }"
+                :to="coursePageRoute(course)"
                 class="outline-none after:absolute after:inset-0 after:content-['']"
               >
                 {{ course.name }}
@@ -110,7 +120,9 @@ async function confirmDelete() {
               {{ course.code }}
             </Badge>
           </div>
-          <CardDescription>{{ course.teachers.join(', ') }}</CardDescription>
+          <CardDescription v-if="course.teachers.length">
+            {{ course.teachers.join(', ') }}
+          </CardDescription>
         </div>
 
         <div class="relative z-10 flex shrink-0 gap-1">
@@ -132,15 +144,15 @@ async function confirmDelete() {
       </Card>
     </div>
 
-    <CourseFormDialog v-model:open="formOpen" :course="editedCourse" />
+    <CourseFormDialog v-model:open="formOpen" :kind="kind" :course="editedCourse" />
 
     <AlertDialog v-model:open="deleteOpen">
       <AlertDialogContent>
         <AlertDialogHeader>
           <AlertDialogTitle>
-            {{ $t('courses.delete-title', { name: deletedCourse?.name }) }}
+            {{ $t(`${k}.delete-title`, { name: deletedCourse?.name }) }}
           </AlertDialogTitle>
-          <AlertDialogDescription>{{ $t('courses.delete-description') }}</AlertDialogDescription>
+          <AlertDialogDescription>{{ $t(`${k}.delete-description`) }}</AlertDialogDescription>
         </AlertDialogHeader>
         <AlertDialogFooter>
           <AlertDialogCancel>{{ $t('common.cancel') }}</AlertDialogCancel>
diff --git a/frontend/src/views/HomeView.vue b/frontend/src/views/HomeView.vue
index 650cb48..68259a2 100644
--- a/frontend/src/views/HomeView.vue
+++ b/frontend/src/views/HomeView.vue
@@ -10,7 +10,7 @@ import { sections } from '@/router/navigation'
       <p class="text-muted-foreground">{{ $t('home.subtitle') }}</p>
     </div>
 
-    <div class="grid gap-4 sm:grid-cols-2 xl:grid-cols-4">
+    <div class="grid gap-4 sm:grid-cols-2 lg:grid-cols-3 2xl:grid-cols-5">
       <RouterLink
         v-for="section in sections"
         :key="section.name"
diff --git a/frontend/src/views/LectureNoteView.vue b/frontend/src/views/LectureNoteView.vue
index 961910f..daf4852 100644
--- a/frontend/src/views/LectureNoteView.vue
+++ b/frontend/src/views/LectureNoteView.vue
@@ -23,6 +23,7 @@ import {
   useLectureNoteMutations,
   useCourseFiles,
 } from '@/services/api/course-files'
+import { coursePageRoute, noteRoute } from '@/utils/routes'
 import type { CourseFile } from '@/utils/types'
 
 const props = defineProps<{ id: number; noteId?: number }>()
@@ -78,11 +79,8 @@ watch(
   { immediate: true },
 )
 
-const backTo = computed(() => ({
-  name: 'course',
-  params: { id: props.id },
-  query: { tab: 'files' },
-}))
+const kind = computed(() => (route.name === 'association-note' ? 'association' : 'course'))
+const backTo = computed(() => coursePageRoute({ id: props.id, kind: kind.value }, 'files'))
 
 async function submit() {
   if (!title.value.trim()) {
@@ -97,11 +95,9 @@ async function submit() {
     saved.value = { title: title.value, content: content.value }
     pdfError.value = result.pdf_error ?? undefined
     if (isNew.value) {
-      await router.replace({
-        name: 'course-note',
-        params: { id: props.id, noteId: result.note.id },
-        query: result.pdf_error ? { edit: '1' } : {},
-      })
+      await router.replace(
+        noteRoute({ id: props.id, kind: kind.value }, result.note.id, !!result.pdf_error),
+      )
     }
     if (result.pdf_error) {
       toast.warning(t('notes.saved-without-pdf'))
@@ -153,7 +149,7 @@ function pdfUrl(note: CourseFile) {
       <Button variant="ghost" as-child>
         <RouterLink :to="backTo">
           <ArrowLeft />
-          {{ course?.name ?? $t('course.back') }}
+          {{ course?.name ?? $t(`${kind}.back`) }}
         </RouterLink>
       </Button>
 
diff --git a/frontend/src/views/PomodoroView.vue b/frontend/src/views/PomodoroView.vue
index 5125c92..ccff3fd 100644
--- a/frontend/src/views/PomodoroView.vue
+++ b/frontend/src/views/PomodoroView.vue
@@ -1,7 +1,461 @@
 <script setup lang="ts">
-import PagePlaceholder from '@/components/PagePlaceholder.vue'
+/**
+ * Reverse pomodoro: a timer counting up the focus on a task, with the time of day, in a
+ * quiet page. A ring fills up every 25 minutes and suggests a break, a fifth of the
+ * focus time. The notes and slides of the course open next to the clock.
+ *
+ * `?task=<id>` starts a session on the task (see `services/focus.ts`).
+ */
+import { computed, onBeforeUnmount, ref, useTemplateRef, watch } from 'vue'
+import { useI18n } from 'vue-i18n'
+import { useRoute, useRouter } from 'vue-router'
+import { onKeyStroke, useFullscreen } from '@vueuse/core'
+import { toast } from 'vue-sonner'
+import {
+  ExternalLink,
+  FileText,
+  FolderOpen,
+  Loader2,
+  Maximize,
+  Minimize,
+  Pause,
+  Play,
+  Square,
+  Timer,
+  X,
+} from '@lucide/vue'
+
+import TagBadge from '@/components/course/TagBadge.vue'
+import { Button } from '@/components/ui/button'
+import { Skeleton } from '@/components/ui/skeleton'
+import { lectureNotePdfUrl, useCourseFiles } from '@/services/api/course-files'
+import { useTags } from '@/services/api/tags'
+import { useRefreshTasks, useTodoTasks } from '@/services/api/tasks'
+import { CYCLE_SECONDS, formatDuration, formatSpent, useFocus } from '@/services/focus'
+import { formatRelative } from '@/utils/dates'
+import { coursePageRoute, tasksTab } from '@/utils/routes'
+import type { CourseFile } from '@/utils/types'
+
+const { t, locale } = useI18n()
+const route = useRoute()
+const router = useRouter()
+const { tagsById } = useTags()
+const refreshTasks = useRefreshTasks()
+const focus = useFocus()
+const { session, elapsed, pauseElapsed, isRunning, pending, now } = focus
+
+const task = computed(() => session.value?.task ?? null)
+
+/** Shows the errors of an action: TimeTagger ones as a warning, the session runs anyway */
+async function run(action: () => Promise<string | null>) {
+  const courseId = task.value?.course.id
+  try {
+    const timetaggerError = await action()
+    if (timetaggerError) {
+      toast.warning(t('focus.timetagger-error'), { description: timetaggerError })
+    }
+  } catch (err) {
+    toast.error(t('focus.error'), { description: err instanceof Error ? err.message : undefined })
+  } finally {
+    if (courseId !== undefined) refreshTasks(courseId)
+  }
+}
+
+// `?task=<id>`: starts working on the task, then leaves the url clean so a reload does
+// not start it again
+watch(
+  () => route.query.task,
+  async (value) => {
+    const taskId = Number(value)
+    if (!value || !Number.isInteger(taskId)) return
+    await router.replace({ query: {} })
+    if (task.value?.task_id === taskId) {
+      if (!isRunning.value) await run(focus.resume)
+      return
+    }
+    await run(() => focus.start(taskId))
+  },
+  { immediate: true },
+)
+
+function togglePause() {
+  if (pending.value || !session.value) return
+  run(isRunning.value ? focus.pause : focus.resume)
+}
+
+async function stop() {
+  const seconds = elapsed.value
+  const name = task.value?.name
+  await run(focus.stop)
+  if (!session.value) {
+    toast.success(t('focus.stopped', { time: formatSpent(seconds) }), { description: name })
+  }
+  openedFile.value = undefined
+}
+
+onKeyStroke(' ', (event) => {
+  const target = event.target as HTMLElement
+  if (target.closest('input, textarea, button, a, [contenteditable]')) return
+  event.preventDefault()
+  togglePause()
+})
+
+// The ring fills up once per cycle: a break is suggested each time it is full
+const cycles = computed(() => Math.floor(elapsed.value / CYCLE_SECONDS))
+const cycleProgress = computed(() => (elapsed.value % CYCLE_SECONDS) / CYCLE_SECONDS)
+const suggestedBreak = computed(() => Math.max(5 * 60, Math.round(elapsed.value / 5)))
+
+watch(cycles, (count, previous) => {
+  if (isRunning.value && previous !== undefined && count > previous) {
+    toast(t('focus.cycle-done', { n: count }), { description: t('focus.cycle-hint') })
+  }
+})
+
+const RADIUS = 46
+const CIRCUMFERENCE = 2 * Math.PI * RADIUS
+
+const clock = computed(() =>
+  new Intl.DateTimeFormat(locale.value, { hour: '2-digit', minute: '2-digit' }).format(now.value),
+)
+const today = computed(() =>
+  new Intl.DateTimeFormat(locale.value, { weekday: 'long', day: 'numeric', month: 'long' }).format(
+    now.value,
+  ),
+)
+
+/** Time spent on the task, this session included */
+const totalSpent = computed(() => (session.value?.spentBefore ?? 0) + elapsed.value)
+
+// The time in the tab title, visible from the other tabs
+const originalTitle = document.title
+watch(
+  [elapsed, isRunning, session],
+  () => {
+    document.title = session.value
+      ? `${isRunning.value ? '⏱' : '⏸'} ${formatDuration(elapsed.value)} · ${originalTitle}`
+      : originalTitle
+  },
+  { immediate: true },
+)
+onBeforeUnmount(() => (document.title = originalTitle))
+
+const container = useTemplateRef<HTMLElement>('container')
+const { isFullscreen, toggle: toggleFullscreen } = useFullscreen(container)
+
+// Resources of the course: its notes (and soon its slides), opened next to the clock
+const showResources = ref(true)
+const { data: files, isPending: filesPending } = useCourseFiles(() => task.value?.course.id)
+const openedFile = ref<CourseFile>()
+
+function canOpen(file: CourseFile) {
+  return file.kind === 'note' && file.has_pdf
+}
+
+// The small clock is next to the resources: no resource without them
+watch([() => task.value?.course.id, showResources], () => (openedFile.value = undefined))
+
+// Nothing running: pick a task
+const { data: todos, isPending: todosPending } = useTodoTasks()
+const choices = computed(() =>
+  (todos.value ?? []).flatMap(({ course, task }) => [
+    { course, task, parent: undefined as string | undefined },
+    ...task.subtasks
+      .filter((subtask) => !subtask.done)
+      .map((subtask) => ({ course, task: subtask, parent: task.name })),
+  ]),
+)
 </script>
 
 <template>
-  <PagePlaceholder title="nav.pomodoro" />
+  <div
+    ref="container"
+    class="relative -m-4 flex min-h-[calc(100svh-3.5rem)] flex-col bg-gradient-to-b from-muted/40 to-background md:-m-6"
+  >
+    <!-- Top bar: quiet, out of the way -->
+    <div class="flex items-center gap-2 px-4 pt-4 md:px-6">
+      <span class="text-sm text-muted-foreground first-letter:uppercase">{{ today }}</span>
+      <div class="ml-auto flex gap-1">
+        <Button
+          v-if="task"
+          variant="ghost"
+          size="sm"
+          :class="{ 'bg-accent': showResources }"
+          :aria-pressed="showResources"
+          @click="showResources = !showResources"
+        >
+          <FolderOpen />
+          <span class="hidden sm:inline">{{ $t('focus.resources') }}</span>
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon-sm"
+          :title="isFullscreen ? $t('focus.exit-fullscreen') : $t('focus.fullscreen')"
+          @click="toggleFullscreen()"
+        >
+          <Minimize v-if="isFullscreen" />
+          <Maximize v-else />
+          <span class="sr-only">{{ $t('focus.fullscreen') }}</span>
+        </Button>
+      </div>
+    </div>
+
+    <div
+      class="grid flex-1 gap-4 p-4 md:p-6"
+      :class="{ 'lg:grid-cols-[minmax(0,1fr)_20rem]': task && showResources }"
+    >
+      <!-- A resource opened: it takes the room, the clock moves to the side -->
+      <div v-if="openedFile" class="flex min-h-[70svh] flex-col gap-2">
+        <div class="flex items-center gap-2">
+          <FileText class="size-4 shrink-0 text-muted-foreground" />
+          <span class="truncate text-sm font-medium">{{ openedFile.name }}</span>
+          <Button variant="ghost" size="icon-sm" class="ml-auto" as-child>
+            <a
+              :href="lectureNotePdfUrl(openedFile)"
+              target="_blank"
+              rel="noopener noreferrer"
+              :title="$t('focus.open-tab')"
+            >
+              <ExternalLink />
+              <span class="sr-only">{{ $t('focus.open-tab') }}</span>
+            </a>
+          </Button>
+          <Button
+            variant="ghost"
+            size="icon-sm"
+            :title="$t('focus.close-resource')"
+            @click="openedFile = undefined"
+          >
+            <X />
+            <span class="sr-only">{{ $t('focus.close-resource') }}</span>
+          </Button>
+        </div>
+        <iframe
+          :src="lectureNotePdfUrl(openedFile)"
+          :title="openedFile.name"
+          class="w-full flex-1 rounded-lg border bg-muted"
+        />
+      </div>
+
+      <!-- The clock -->
+      <div v-show="!openedFile" class="flex flex-col items-center justify-center gap-6 text-center">
+        <template v-if="session">
+          <div class="flex max-w-xl flex-col items-center gap-2">
+            <template v-if="task">
+              <RouterLink
+                :to="coursePageRoute(task.course, tasksTab(task.course.kind))"
+                class="text-sm text-muted-foreground hover:underline"
+              >
+                <span v-if="task.course.code" class="font-mono">{{ task.course.code }} · </span>
+                {{ task.course.name }}
+              </RouterLink>
+              <h2 class="text-2xl font-semibold text-balance md:text-3xl">
+                <span v-if="task.parent_name" class="text-muted-foreground">
+                  {{ task.parent_name }} ›
+                </span>
+                {{ task.name }}
+              </h2>
+              <div class="flex flex-wrap justify-center gap-1">
+                <template v-for="tagId in task.tag_ids" :key="tagId">
+                  <TagBadge v-if="tagsById.get(tagId)" :tag="tagsById.get(tagId)!" />
+                </template>
+              </div>
+            </template>
+            <h2 v-else class="text-2xl font-semibold md:text-3xl">{{ $t('focus.free') }}</h2>
+          </div>
+
+          <!-- Ring of the current cycle, the focus time inside -->
+          <div class="relative size-72 sm:size-96">
+            <svg viewBox="0 0 100 100" class="size-full -rotate-90" aria-hidden="true">
+              <circle
+                cx="50"
+                cy="50"
+                :r="RADIUS"
+                fill="none"
+                class="stroke-muted"
+                stroke-width="2"
+              />
+              <circle
+                cx="50"
+                cy="50"
+                :r="RADIUS"
+                fill="none"
+                stroke-width="2.5"
+                stroke-linecap="round"
+                class="transition-[stroke-dashoffset] duration-1000 ease-linear"
+                :class="isRunning ? 'stroke-primary' : 'stroke-muted-foreground/40'"
+                :stroke-dasharray="CIRCUMFERENCE"
+                :stroke-dashoffset="CIRCUMFERENCE * (1 - cycleProgress)"
+              />
+            </svg>
+            <div class="absolute inset-0 flex flex-col items-center justify-center gap-2">
+              <span
+                class="font-mono text-6xl font-light tracking-tight tabular-nums sm:text-7xl"
+                :class="{ 'text-muted-foreground': !isRunning }"
+                role="timer"
+                :aria-label="$t('focus.elapsed')"
+              >
+                {{ formatDuration(elapsed) }}
+              </span>
+              <span class="text-lg text-muted-foreground tabular-nums">{{ clock }}</span>
+              <span
+                v-if="cycles"
+                class="flex items-center gap-1"
+                :title="$t('focus.cycles', { n: cycles })"
+              >
+                <span
+                  v-for="i in Math.min(cycles, 8)"
+                  :key="i"
+                  class="size-2 rounded-full bg-primary/70"
+                />
+                <span v-if="cycles > 8" class="text-xs text-muted-foreground"
+                  >+{{ cycles - 8 }}</span
+                >
+              </span>
+            </div>
+          </div>
+
+          <p v-if="!isRunning" class="text-sm text-muted-foreground">
+            {{ $t('focus.paused', { time: formatDuration(pauseElapsed) }) }}
+            · {{ $t('focus.suggested-break', { time: formatSpent(suggestedBreak) }) }}
+          </p>
+
+          <div class="flex items-center gap-3">
+            <Button
+              size="lg"
+              class="h-14 min-w-40 rounded-full text-base"
+              :disabled="pending"
+              @click="togglePause"
+            >
+              <Loader2 v-if="pending" class="animate-spin" />
+              <Pause v-else-if="isRunning" />
+              <Play v-else />
+              {{ isRunning ? $t('focus.pause') : $t('focus.resume') }}
+            </Button>
+            <Button
+              size="lg"
+              variant="outline"
+              class="h-14 rounded-full"
+              :disabled="pending"
+              @click="stop"
+            >
+              <Square />
+              {{ $t('focus.stop') }}
+            </Button>
+          </div>
+
+          <p class="flex flex-wrap justify-center gap-x-3 text-xs text-muted-foreground">
+            <span v-if="task">{{ $t('focus.total', { time: formatSpent(totalSpent) }) }}</span>
+            <span v-if="task?.timetagger_enabled" class="flex items-center gap-1">
+              <span
+                class="size-1.5 rounded-full"
+                :class="session.record ? 'bg-green-500' : 'bg-muted-foreground/50'"
+              />
+              TimeTagger
+            </span>
+            <span class="hidden md:inline">{{ $t('focus.space-hint') }}</span>
+          </p>
+        </template>
+
+        <!-- Nothing running -->
+        <template v-else>
+          <div class="flex flex-col items-center gap-1">
+            <span class="font-mono text-7xl font-light tracking-tight tabular-nums sm:text-8xl">
+              {{ clock }}
+            </span>
+            <p class="text-muted-foreground">{{ $t('focus.pick') }}</p>
+          </div>
+
+          <div class="flex w-full max-w-lg flex-col gap-2 text-left">
+            <div v-if="todosPending" class="flex flex-col gap-2">
+              <Skeleton v-for="i in 3" :key="i" class="h-12 rounded-lg" />
+            </div>
+            <ul v-else class="flex max-h-[45svh] flex-col gap-1.5 overflow-y-auto">
+              <li v-for="choice in choices" :key="choice.task.id">
+                <button
+                  type="button"
+                  class="flex w-full items-center gap-3 rounded-lg border bg-card px-3 py-2 text-left transition-colors hover:bg-accent disabled:opacity-60"
+                  :disabled="pending"
+                  @click="run(() => focus.start(choice.task.id))"
+                >
+                  <Timer class="size-4 shrink-0 text-muted-foreground" />
+                  <span class="flex min-w-0 flex-1 flex-col">
+                    <span class="truncate text-sm font-medium">
+                      <span v-if="choice.parent" class="text-muted-foreground">
+                        {{ choice.parent }} ›
+                      </span>
+                      {{ choice.task.name }}
+                    </span>
+                    <span class="truncate text-xs text-muted-foreground">
+                      <span class="font-mono">{{ choice.course.code ?? choice.course.name }}</span>
+                      <template v-if="choice.task.deadline">
+                        · {{ formatRelative(choice.task.deadline, locale) }}
+                      </template>
+                    </span>
+                  </span>
+                </button>
+              </li>
+              <li v-if="!choices.length" class="py-2 text-center text-sm text-muted-foreground">
+                {{ $t('focus.no-task') }}
+              </li>
+            </ul>
+            <Button variant="outline" :disabled="pending" @click="run(() => focus.start(null))">
+              <Play />
+              {{ $t('focus.start-free') }}
+            </Button>
+          </div>
+        </template>
+      </div>
+
+      <!-- Side: the clock when a resource is opened, and the resources -->
+      <aside v-if="task && showResources" class="flex min-w-0 flex-col gap-4">
+        <div v-if="openedFile" class="flex items-center gap-3 rounded-xl border bg-card p-3">
+          <span
+            class="font-mono text-3xl font-light tabular-nums"
+            :class="{ 'text-muted-foreground': !isRunning }"
+          >
+            {{ formatDuration(elapsed) }}
+          </span>
+          <span class="text-sm text-muted-foreground tabular-nums">{{ clock }}</span>
+          <Button
+            size="icon"
+            variant="secondary"
+            class="ml-auto rounded-full"
+            :disabled="pending"
+            :title="isRunning ? $t('focus.pause') : $t('focus.resume')"
+            @click="togglePause"
+          >
+            <Pause v-if="isRunning" />
+            <Play v-else />
+          </Button>
+        </div>
+
+        <div class="flex flex-col gap-2 rounded-xl border bg-card p-3">
+          <h3 class="text-sm font-medium">{{ $t('focus.resources') }}</h3>
+          <div v-if="filesPending" class="flex flex-col gap-2">
+            <Skeleton v-for="i in 3" :key="i" class="h-9" />
+          </div>
+          <p v-else-if="!files?.length" class="text-sm text-muted-foreground">
+            {{ $t('focus.no-resource') }}
+          </p>
+          <ul v-else class="-mx-1 flex flex-col">
+            <li v-for="file in files" :key="file.id">
+              <button
+                type="button"
+                class="flex w-full items-center gap-2 rounded-md px-2 py-1.5 text-left text-sm transition-colors hover:bg-accent disabled:cursor-not-allowed disabled:opacity-50"
+                :class="{ 'bg-accent font-medium': openedFile?.id === file.id }"
+                :disabled="!canOpen(file)"
+                @click="openedFile = file"
+              >
+                <FileText class="size-4 shrink-0 text-muted-foreground" />
+                <span class="min-w-0 flex-1 truncate">{{ file.name }}</span>
+                <template v-for="tagId in file.tag_ids" :key="tagId">
+                  <TagBadge v-if="tagsById.get(tagId)" :tag="tagsById.get(tagId)!" />
+                </template>
+              </button>
+            </li>
+          </ul>
+        </div>
+      </aside>
+    </div>
+  </div>
 </template>
diff --git a/src/api/helpers.rs b/src/api/helpers.rs
index c19c832..4237c34 100644
--- a/src/api/helpers.rs
+++ b/src/api/helpers.rs
@@ -21,6 +21,7 @@ pub fn error_response<T>(fn_name: &str, err: ControllerError) -> Result<T, (Stat
         ControllerError::Grade(err) => Some(err.to_string()),
         ControllerError::Task(err) => Some(err.to_string()),
         ControllerError::LectureNote(err) => Some(err.to_string()),
+        ControllerError::Focus(err) => Some(err.to_string()),
         _ => None,
     };
     match (invalid, err) {
diff --git a/src/api/models.rs b/src/api/models.rs
index 0482724..97911f2 100644
--- a/src/api/models.rs
+++ b/src/api/models.rs
@@ -6,8 +6,9 @@ use schemars::JsonSchema;
 use serde::Deserialize;
 
 use crate::core::models::{
-    course::{CourseData, CourseId},
+    course::{CourseData, CourseId, CourseKind},
     course_file::CourseFileId,
+    focus::TimetaggerRecord,
     grade::{GradeData, GradeId},
     tag::TagId,
     task::{TaskData, TaskId},
@@ -48,12 +49,15 @@ pub struct PeriodQuery {
     pub to: DateTime<Utc>,
 }
 
-/// A course, without its slots: they are added and removed one by one
+/// A course or an association, without its slots: they are added and removed one by one
 #[derive(Deserialize, JsonSchema)]
 pub struct CourseBody {
+    /// `course` by default. Cannot be changed once created.
+    pub kind: Option<CourseKind>,
     pub name: String,
     pub code: Option<String>,
-    /// At least one
+    /// At least one for a course
+    #[serde(default)]
     pub teachers: Vec<String>,
     /// http(s) url of the main page of the course
     pub main_page_url: Option<String>,
@@ -104,6 +108,15 @@ pub struct CreateTaskBody {
     pub task: TaskBody,
 }
 
+/// End (or pause) of a focus session
+#[derive(Deserialize, JsonSchema)]
+pub struct FocusStopBody {
+    /// Length of the session, at most 24 hours
+    pub seconds: u32,
+    /// Record returned when the session started, to stop it
+    pub timetagger: Option<TimetaggerRecord>,
+}
+
 #[derive(Deserialize, JsonSchema)]
 pub struct LectureNoteBody {
     /// Subtitle of the pdf, e.g. "Lecture 2 Notes: Memory subsystem"
@@ -115,6 +128,7 @@ pub struct LectureNoteBody {
 impl From<CourseBody> for CourseData {
     fn from(value: CourseBody) -> Self {
         CourseData {
+            kind: value.kind.unwrap_or(CourseKind::Course),
             name: value.name,
             code: value.code,
             teachers: value.teachers,
diff --git a/src/api/tasks.rs b/src/api/tasks.rs
index 3ab0619..2144cf5 100644
--- a/src/api/tasks.rs
+++ b/src/api/tasks.rs
@@ -1,10 +1,12 @@
 //! Tasks of a course. Every change returns all the tasks of the course, nested and
 //! sorted, with the deadlines: the page never needs a second request.
+//!
+//! The focus sessions of the pomodoro are counted on the tasks, and in TimeTagger.
 
 use aide::{
     axum::{
         ApiRouter,
-        routing::{get_with, put_with},
+        routing::{get_with, post_with, put_with},
     },
     transform::TransformOperation,
 };
@@ -17,11 +19,14 @@ use axum::{
 use crate::{
     api::{
         helpers::{desc, error_response},
-        models::{CoursePath, CreateTaskBody, PeriodQuery, TaskBody, TaskPath},
+        models::{CoursePath, CreateTaskBody, FocusStopBody, PeriodQuery, TaskBody, TaskPath},
     },
     core::{
         controller::AppController,
-        models::task::{CalendarTask, CourseTasks},
+        models::{
+            focus::{FocusStart, FocusStop},
+            task::{CalendarTask, CourseTasks, TodoTask},
+        },
     },
 };
 
@@ -31,6 +36,10 @@ pub fn routes() -> ApiRouter {
             "/api/tasks",
             get_with(get_calendar_tasks, get_calendar_tasks_docs),
         )
+        .api_route(
+            "/api/tasks/todo",
+            get_with(get_todo_tasks, get_todo_tasks_docs),
+        )
         .api_route(
             "/api/courses/{id}/tasks",
             get_with(get_course_tasks, get_course_tasks_docs)
@@ -40,6 +49,68 @@ pub fn routes() -> ApiRouter {
             "/api/tasks/{id}",
             put_with(update_task, update_task_docs).delete_with(delete_task, delete_task_docs),
         )
+        .api_route(
+            "/api/tasks/{id}/focus",
+            post_with(start_focus, start_focus_docs),
+        )
+        .api_route(
+            "/api/tasks/{id}/focus/stop",
+            post_with(stop_focus, stop_focus_docs),
+        )
+}
+
+async fn get_todo_tasks(
+    controller: AppController,
+) -> Result<Json<Vec<TodoTask>>, (StatusCode, String)> {
+    match controller.get_todo_tasks().await {
+        Ok(tasks) => Ok(Json(tasks)),
+        Err(err) => error_response("get_todo_tasks", err),
+    }
+}
+
+fn get_todo_tasks_docs(op: TransformOperation) -> TransformOperation {
+    op.tag("Tasks").summary(
+        "Get the tasks not done of every course and association, with their subtasks, \
+         the closest deadline first",
+    )
+}
+
+async fn start_focus(
+    controller: AppController,
+    Path(path): Path<TaskPath>,
+) -> Result<Json<FocusStart>, (StatusCode, String)> {
+    match controller.start_focus(path.id).await {
+        Ok(focus) => Ok(Json(focus)),
+        Err(err) => error_response("start_focus", err),
+    }
+}
+
+fn start_focus_docs(op: TransformOperation) -> TransformOperation {
+    op.tag("Tasks")
+        .summary("Start a focus session on a task, and its TimeTagger record")
+        .description("The session starts even when TimeTagger fails: see `timetagger_error`.")
+        .response_with::<404, String, _>(desc("The task does not exist"))
+}
+
+async fn stop_focus(
+    controller: AppController,
+    Path(path): Path<TaskPath>,
+    Json(body): Json<FocusStopBody>,
+) -> Result<Json<FocusStop>, (StatusCode, String)> {
+    match controller
+        .stop_focus(path.id, body.seconds, body.timetagger)
+        .await
+    {
+        Ok(focus) => Ok(Json(focus)),
+        Err(err) => error_response("stop_focus", err),
+    }
+}
+
+fn stop_focus_docs(op: TransformOperation) -> TransformOperation {
+    op.tag("Tasks")
+        .summary("End or pause a focus session: its time is added to the task")
+        .response_with::<400, String, _>(desc("The session is too long"))
+        .response_with::<404, String, _>(desc("The task does not exist"))
 }
 
 async fn get_calendar_tasks(
diff --git a/src/core/controller/course_files.rs b/src/core/controller/course_files.rs
index 722e947..783a3ea 100644
--- a/src/core/controller/course_files.rs
+++ b/src/core/controller/course_files.rs
@@ -1,16 +1,17 @@
 //! Files of a course. For now only the lecture notes: markdown written in the app,
 //! rendered to pdf with the course template, and tagged `notes`.
 //!
-//! Both files of a note live in the storage, next to the other files of the course:
-//! `courses/{course}/notes/{note}.md` and `.pdf`. The `.md` holds the front matter
-//! expected by the template, so it can also be rendered by hand with `mdpdf`. The
-//! editor only sees what comes after it.
+//! Both files of a note live in the folder of the course, named after the note:
+//! `Cours/CS-477 Advanced OS/Notes/Lecture 1 Notes - Intro.md` and `.pdf`. They are
+//! moved when the note is renamed. The `.md` holds the front matter expected by the
+//! template, so it can also be rendered by hand with `mdpdf`. The editor only sees what
+//! comes after it.
 
 use thiserror::Error;
 use tracing::error;
 
 use crate::core::{
-    controller::{ControllerError, courses::course_dir},
+    controller::{ControllerError, courses::file_name},
     models::{
         course::{Course, CourseId},
         course_file::{CourseFile, CourseFileId, FileKind, LectureNoteContent, SavedLectureNote},
@@ -28,12 +29,20 @@ pub struct NotesSettings {
     pub logo: Option<String>,
 }
 
-fn markdown_path(note: &CourseFile) -> String {
-    format!("{}/notes/{}.md", course_dir(note.course_id), note.id)
+/// Sub folder of the course holding the notes
+const NOTES_FOLDER: &str = "Notes";
+
+fn markdown_path(course: &Course, path: &str) -> String {
+    format!("{}/{path}.md", course.folder)
 }
 
-fn pdf_path(note: &CourseFile) -> String {
-    format!("{}/notes/{}.pdf", course_dir(note.course_id), note.id)
+fn pdf_path(course: &Course, path: &str) -> String {
+    format!("{}/{path}.pdf", course.folder)
+}
+
+/// Path of a note in the folder of its course, without extension
+fn note_path(title: &str) -> String {
+    format!("{NOTES_FOLDER}/{}", file_name(title))
 }
 
 impl super::AppController {
@@ -63,7 +72,12 @@ impl super::AppController {
         id: CourseFileId,
     ) -> Result<LectureNoteContent, ControllerError> {
         let note = self.get_note(id).await?;
-        let content = match self.storage.read_file(&markdown_path(&note)).await {
+        let course = self.db.get_course(note.course_id).await?;
+        let content = match self
+            .storage
+            .read_file(&markdown_path(&course, &note.path))
+            .await
+        {
             Ok(bytes) => String::from_utf8_lossy(&bytes).into_owned(),
             // Lost file: the note can still be rewritten
             Err(RepositoryError::NotFound(_)) => String::new(),
@@ -78,8 +92,9 @@ impl super::AppController {
     /// `NotFound` if the note does not exist or its last rendering failed
     pub async fn get_lecture_note_pdf(&self, id: CourseFileId) -> Result<Vec<u8>, ControllerError> {
         let note = self.get_note(id).await?;
+        let course = self.db.get_course(note.course_id).await?;
         self.storage
-            .read_file(&pdf_path(&note))
+            .read_file(&pdf_path(&course, &note.path))
             .await
             .map_err(Into::into)
     }
@@ -92,10 +107,12 @@ impl super::AppController {
     ) -> Result<SavedLectureNote, ControllerError> {
         let title = validate_title(title)?;
         let course = self.db.get_course(course_id).await?;
+        let path = note_path(&title);
+        self.check_path_free(course_id, &path, None).await?;
         let notes_tag = self.db.get_tag_id(NOTES_TAG).await?;
         let note = self
             .db
-            .create_lecture_note(course_id, title.clone(), &[notes_tag])
+            .create_lecture_note(course_id, title.clone(), path, &[notes_tag])
             .await?;
         self.save_lecture_note(&course, note, title, content).await
     }
@@ -109,14 +126,55 @@ impl super::AppController {
         let title = validate_title(title)?;
         let note = self.get_note(id).await?;
         let course = self.db.get_course(note.course_id).await?;
+
+        // Renamed: its files follow
+        let path = note_path(&title);
+        if path != note.path {
+            self.check_path_free(course.id, &path, Some(id)).await?;
+            for (from, to) in [
+                (
+                    markdown_path(&course, &note.path),
+                    markdown_path(&course, &path),
+                ),
+                (pdf_path(&course, &note.path), pdf_path(&course, &path)),
+            ] {
+                match self.storage.rename(&from, &to).await {
+                    Ok(()) | Err(RepositoryError::NotFound(_)) => {}
+                    Err(err) => return Err(err.into()),
+                }
+            }
+        }
+        let note = CourseFile { path, ..note };
         self.save_lecture_note(&course, note, title, content).await
     }
 
     pub async fn delete_lecture_note(&self, id: CourseFileId) -> Result<(), ControllerError> {
         let note = self.get_note(id).await?;
+        let course = self.db.get_course(note.course_id).await?;
         self.db.delete_course_file(id).await?;
-        self.storage.delete_file(&markdown_path(&note)).await?;
-        self.storage.delete_file(&pdf_path(&note)).await?;
+        self.storage
+            .delete_file(&markdown_path(&course, &note.path))
+            .await?;
+        self.storage
+            .delete_file(&pdf_path(&course, &note.path))
+            .await?;
+        Ok(())
+    }
+
+    /// `NameTaken` if another file of the course (than `except`) already has this path
+    async fn check_path_free(
+        &self,
+        course_id: CourseId,
+        path: &str,
+        except: Option<CourseFileId>,
+    ) -> Result<(), ControllerError> {
+        let files = self.db.get_course_files(course_id).await?;
+        if files
+            .iter()
+            .any(|file| file.path == path && Some(file.id) != except)
+        {
+            return Err(LectureNotesControllerError::NameTaken.into());
+        }
         Ok(())
     }
 
@@ -130,18 +188,19 @@ impl super::AppController {
         content: String,
     ) -> Result<SavedLectureNote, ControllerError> {
         let markdown = format!("{}{}", self.front_matter(course, &title), content);
+        let pdf = pdf_path(course, &note.path);
         self.storage
-            .write_file(&markdown_path(&note), markdown.as_bytes())
+            .write_file(&markdown_path(course, &note.path), markdown.as_bytes())
             .await?;
 
         let pdf_error = match self.renderer.render(&markdown).await {
-            Ok(pdf) => {
-                self.storage.write_file(&pdf_path(&note), &pdf).await?;
+            Ok(content) => {
+                self.storage.write_file(&pdf, &content).await?;
                 None
             }
             Err(err) => {
                 // No stale pdf that would not match the markdown anymore
-                self.storage.delete_file(&pdf_path(&note)).await?;
+                self.storage.delete_file(&pdf).await?;
                 Some(match err {
                     RenderError::Failed(log) => log,
                     RenderError::Internal(message) => {
@@ -154,7 +213,7 @@ impl super::AppController {
 
         let note = self
             .db
-            .update_lecture_note(note.id, title, pdf_error.is_none())
+            .update_lecture_note(note.id, title, note.path, pdf_error.is_none())
             .await?;
         Ok(SavedLectureNote { note, pdf_error })
     }
@@ -209,6 +268,8 @@ fn validate_title(title: String) -> Result<String, ControllerError> {
 pub enum LectureNotesControllerError {
     #[error("The title of the note is empty")]
     EmptyTitle,
+    #[error("Another file of the course already has this name")]
+    NameTaken,
 }
 
 #[cfg(test)]
diff --git a/src/core/controller/courses.rs b/src/core/controller/courses.rs
index f293fc4..b6b8ae4 100644
--- a/src/core/controller/courses.rs
+++ b/src/core/controller/courses.rs
@@ -1,15 +1,21 @@
-//! Courses and their weekly time slots.
+//! Courses and associations, and their weekly time slots.
+//!
+//! Each one has a folder in the storage named after it, where its files live:
+//! `Cours/CS-477 Advanced operating systems`, `Associations/AGEPoly`. The folder is
+//! moved when the course is renamed.
 
 use chrono::NaiveTime;
 use thiserror::Error;
+use tracing::error;
 
 use crate::core::{
     controller::{ControllerError, is_http_url, non_blank},
     models::{
-        course::{Course, CourseData, CourseId},
+        course::{Course, CourseData, CourseId, CourseKind},
         tag::{TagId, TagScope},
         time_slot::{TimeSlotData, TimeSlotId},
     },
+    repositories::RepositoryError,
 };
 
 /// The timetable shows monday to friday...
@@ -19,9 +25,43 @@ const LAST_WEEKDAY: u8 = 5;
 const DAY_START: NaiveTime = NaiveTime::from_hms_opt(8, 0, 0).unwrap();
 const DAY_END: NaiveTime = NaiveTime::from_hms_opt(19, 0, 0).unwrap();
 
-/// Directory of the files of a course in the storage
-pub(crate) fn course_dir(id: CourseId) -> String {
-    format!("courses/{id}")
+/// Longest name of a file or folder in the storage, in characters
+const MAX_FILE_NAME: usize = 120;
+
+/// Folder of a course in the storage, e.g. `Cours/CS-477 Advanced operating systems`
+fn course_folder(course: &CourseData) -> String {
+    let root = match course.kind {
+        CourseKind::Course => "Cours",
+        CourseKind::Association => "Associations",
+    };
+    let name = match &course.code {
+        Some(code) => format!("{code} {}", course.name),
+        None => course.name.clone(),
+    };
+    format!("{root}/{}", file_name(&name))
+}
+
+/// A name usable as a file or folder name on any NAS (samba included): without the
+/// characters Windows forbids, e.g. "Notes: memory/cache" -> "Notes - memory-cache"
+pub(crate) fn file_name(name: &str) -> String {
+    let replaced: String = name
+        .replace(':', " - ")
+        .chars()
+        .map(|c| match c {
+            '/' | '\\' | '*' | '?' | '"' | '<' | '>' | '|' => '-',
+            c if c.is_control() => ' ',
+            c => c,
+        })
+        .collect();
+    let collapsed = replaced.split_whitespace().collect::<Vec<_>>().join(" ");
+    let truncated: String = collapsed.chars().take(MAX_FILE_NAME).collect();
+    // A trailing dot or space is dropped by windows
+    let trimmed = truncated.trim_matches(|c: char| c == '.' || c == ' ');
+    if trimmed.is_empty() {
+        "Sans titre".to_owned()
+    } else {
+        trimmed.to_owned()
+    }
 }
 
 impl super::AppController {
@@ -35,22 +75,73 @@ impl super::AppController {
 
     pub async fn create_course(&self, course: CourseData) -> Result<Course, ControllerError> {
         let course = validate_course(course)?;
-        self.db.create_course(course).await.map_err(Into::into)
+        let folder = course_folder(&course);
+        self.check_folder_free(&folder, None).await?;
+        self.db
+            .create_course(course, &folder)
+            .await
+            .map_err(Into::into)
     }
 
+    /// Replaces a course, keeping its kind. Its folder follows its new name.
     pub async fn update_course(
         &self,
         id: CourseId,
         course: CourseData,
     ) -> Result<Course, ControllerError> {
-        let course = validate_course(course)?;
-        self.db.update_course(id, course).await.map_err(Into::into)
+        let existing = self.db.get_course(id).await?;
+        let course = validate_course(CourseData {
+            kind: existing.kind,
+            ..course
+        })?;
+        let folder = course_folder(&course);
+        if folder == existing.folder {
+            return self
+                .db
+                .update_course(id, course, &folder)
+                .await
+                .map_err(Into::into);
+        }
+
+        self.check_folder_free(&folder, Some(id)).await?;
+        let moved = match self.storage.rename(&existing.folder, &folder).await {
+            Ok(()) => true,
+            // No file yet
+            Err(RepositoryError::NotFound(_)) => false,
+            Err(err) => return Err(err.into()),
+        };
+        match self.db.update_course(id, course, &folder).await {
+            Ok(course) => Ok(course),
+            Err(err) => {
+                if moved && let Err(err) = self.storage.rename(&folder, &existing.folder).await {
+                    error!("Unable to move {folder} back to {}: {err}", existing.folder);
+                }
+                Err(err.into())
+            }
+        }
     }
 
     /// Deletes the course with everything attached to it, its files included
     pub async fn delete_course(&self, id: CourseId) -> Result<(), ControllerError> {
+        let course = self.db.get_course(id).await?;
         self.db.delete_course(id).await?;
-        self.storage.delete_dir(&course_dir(id)).await?;
+        self.storage.delete_dir(&course.folder).await?;
+        Ok(())
+    }
+
+    /// `FolderTaken` if another course (than `except`) already has this folder
+    async fn check_folder_free(
+        &self,
+        folder: &str,
+        except: Option<CourseId>,
+    ) -> Result<(), ControllerError> {
+        let courses = self.db.get_courses().await?;
+        if courses
+            .iter()
+            .any(|course| course.folder == folder && Some(course.id) != except)
+        {
+            return Err(CoursesControllerError::FolderTaken(folder.to_owned()).into());
+        }
         Ok(())
     }
 
@@ -98,7 +189,7 @@ fn validate_course(course: CourseData) -> Result<CourseData, ControllerError> {
         .map(|teacher| teacher.trim().to_owned())
         .filter(|teacher| !teacher.is_empty())
         .collect();
-    if teachers.is_empty() {
+    if teachers.is_empty() && course.kind == CourseKind::Course {
         return Err(CoursesControllerError::NoTeacher.into());
     }
 
@@ -111,6 +202,7 @@ fn validate_course(course: CourseData) -> Result<CourseData, ControllerError> {
     }
 
     Ok(CourseData {
+        kind: course.kind,
         name,
         code: non_blank(course.code),
         teachers,
@@ -133,4 +225,39 @@ pub enum CoursesControllerError {
     InvalidSlotTime,
     #[error("Unknown tag {0}")]
     UnknownTag(TagId),
+    #[error("Another course or association already uses the folder {0}")]
+    FolderTaken(String),
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn file_names_are_safe() {
+        assert_eq!(
+            file_name("Lecture 2 Notes: Memory/cache"),
+            "Lecture 2 Notes - Memory-cache"
+        );
+        assert_eq!(file_name("  a  *b?.  "), "a -b-");
+        assert_eq!(file_name("..."), "Sans titre");
+    }
+
+    #[test]
+    fn folder_of_a_course() {
+        let course = CourseData {
+            kind: CourseKind::Course,
+            name: "Advanced OS".to_owned(),
+            code: Some("CS-477".to_owned()),
+            teachers: Vec::new(),
+            main_page_url: None,
+        };
+        assert_eq!(course_folder(&course), "Cours/CS-477 Advanced OS");
+        let association = CourseData {
+            kind: CourseKind::Association,
+            code: None,
+            ..course
+        };
+        assert_eq!(course_folder(&association), "Associations/Advanced OS");
+    }
 }
diff --git a/src/core/controller/focus.rs b/src/core/controller/focus.rs
new file mode 100644
index 0000000..ca97b56
--- /dev/null
+++ b/src/core/controller/focus.rs
@@ -0,0 +1,183 @@
+//! Focus sessions of the pomodoro. The pomodoro counts up: a session runs from its start
+//! until it is paused or stopped. Its time is added to the task, and counted in
+//! TimeTagger when it is configured, tagged with the course, the tags and the name of the
+//! task (`#cs-477 #homework #exercise-set-3`).
+//!
+//! TimeTagger never blocks a session: when it fails, the error is returned next to the
+//! result, to be shown.
+
+use chrono::Utc;
+use thiserror::Error;
+use tracing::warn;
+
+use crate::core::{
+    controller::ControllerError,
+    models::{
+        focus::{FocusStart, FocusStop, TimetaggerRecord},
+        tag::Tag,
+        task::{Task, TaskId},
+    },
+};
+
+/// Longest session that can be added at once
+const MAX_SESSION_SECONDS: u32 = 24 * 3600;
+
+impl super::AppController {
+    /// Starts a session on a task or a subtask
+    pub async fn start_focus(&self, task_id: TaskId) -> Result<FocusStart, ControllerError> {
+        let task = self.db.get_task(task_id).await?;
+        let parent = match task.parent_id {
+            Some(parent_id) => Some(self.db.get_task(parent_id).await?),
+            None => None,
+        };
+        let course = self.db.get_course(task.course_id).await?;
+        let tag_ids = match &parent {
+            Some(parent) if task.tag_ids.is_empty() => parent.tag_ids.clone(),
+            _ => task.tag_ids.clone(),
+        };
+        let tags: Vec<Tag> = self
+            .db
+            .get_tags(None)
+            .await?
+            .into_iter()
+            .filter(|tag| tag_ids.contains(&tag.id))
+            .collect();
+
+        let started_at = Utc::now();
+        let (timetagger, timetagger_error) = match &self.time_tracker {
+            None => (None, None),
+            Some(tracker) => {
+                let course_tag = course.code.as_deref().unwrap_or(&course.name);
+                let description = description(course_tag, &tags, parent.as_ref(), &task);
+                match tracker.start(&description, started_at).await {
+                    Ok(record) => (Some(record), None),
+                    Err(err) => {
+                        warn!("Unable to start a TimeTagger record: {err}");
+                        (None, Some(err.to_string()))
+                    }
+                }
+            }
+        };
+
+        Ok(FocusStart {
+            course: (&course).into(),
+            task_id: task.id,
+            name: task.name,
+            parent_name: parent.map(|parent| parent.name),
+            tag_ids,
+            time_spent: task.time_spent,
+            started_at,
+            timetagger_enabled: self.time_tracker.is_some(),
+            timetagger,
+            timetagger_error,
+        })
+    }
+
+    /// Ends a session (or pauses it: resuming starts a new one): adds its `seconds` to
+    /// the task and stops its TimeTagger record
+    pub async fn stop_focus(
+        &self,
+        task_id: TaskId,
+        seconds: u32,
+        record: Option<TimetaggerRecord>,
+    ) -> Result<FocusStop, ControllerError> {
+        if seconds > MAX_SESSION_SECONDS {
+            return Err(FocusControllerError::TooLong.into());
+        }
+        let time_spent = self.db.add_time_spent(task_id, seconds as i32).await?;
+
+        let timetagger_error = match (&self.time_tracker, record) {
+            (Some(tracker), Some(record)) => match tracker.stop(&record, Utc::now()).await {
+                Ok(()) => None,
+                Err(err) => {
+                    warn!("Unable to stop the TimeTagger record {}: {err}", record.key);
+                    Some(err.to_string())
+                }
+            },
+            _ => None,
+        };
+        Ok(FocusStop {
+            time_spent,
+            timetagger_error,
+        })
+    }
+}
+
+/// `#cs-477 #homework #exercise-set-3`, the parent task before the subtask
+fn description(course: &str, tags: &[Tag], parent: Option<&Task>, task: &Task) -> String {
+    let mut words: Vec<String> = Vec::new();
+    let names = std::iter::once(course)
+        .chain(
+            tags.iter()
+                .map(|tag| tag.slug.as_deref().unwrap_or(&tag.name.en)),
+        )
+        .chain(parent.map(|parent| parent.name.as_str()))
+        .chain(std::iter::once(task.name.as_str()));
+    for name in names {
+        let word = tag_word(name);
+        if !word.is_empty() && !words.contains(&word) {
+            words.push(word);
+        }
+    }
+    words
+        .iter()
+        .map(|word| format!("#{word}"))
+        .collect::<Vec<_>>()
+        .join(" ")
+}
+
+/// A TimeTagger tag is a single lowercase word: "Exercise set 3" -> "exercise-set-3"
+fn tag_word(name: &str) -> String {
+    name.to_lowercase()
+        .split(|c: char| !c.is_alphanumeric())
+        .filter(|part| !part.is_empty())
+        .collect::<Vec<_>>()
+        .join("-")
+}
+
+#[derive(Error, Debug)]
+pub enum FocusControllerError {
+    #[error("A session lasts at most 24 hours")]
+    TooLong,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::core::models::{localized_string::LocalizedString, tag::TagScope};
+
+    fn task(name: &str) -> Task {
+        Task {
+            id: 1,
+            course_id: 1,
+            parent_id: None,
+            name: name.to_owned(),
+            description: None,
+            links: Vec::new(),
+            deadline: None,
+            done: false,
+            tag_ids: Vec::new(),
+            time_spent: 0,
+            subtasks: Vec::new(),
+        }
+    }
+
+    #[test]
+    fn describes_a_subtask() {
+        let tag = Tag {
+            id: 4,
+            name: LocalizedString {
+                fr: "Devoir".to_owned(),
+                en: "Homework".to_owned(),
+            },
+            color: "#000".to_owned(),
+            slug: Some("homework".to_owned()),
+            scopes: vec![TagScope::Task],
+        };
+        let parent = task("Série 3");
+        assert_eq!(
+            description("CS-477", &[tag], Some(&parent), &task("Exercice 2 (b)")),
+            "#cs-477 #homework #série-3 #exercice-2-b"
+        );
+    }
+}
diff --git a/src/core/controller/mod.rs b/src/core/controller/mod.rs
index 423e77f..b848dd2 100644
--- a/src/core/controller/mod.rs
+++ b/src/core/controller/mod.rs
@@ -13,17 +13,19 @@ use crate::core::{
     controller::{
         course_files::{LectureNotesControllerError, NotesSettings},
         courses::CoursesControllerError,
+        focus::FocusControllerError,
         grades::GradesControllerError,
         tasks::TasksControllerError,
     },
     repositories::{
         DatabaseRepository, RepositoryError, pdf_renderer::PdfRenderer,
-        storage_repository::StorageRepository,
+        storage_repository::StorageRepository, time_tracker::TimeTracker,
     },
 };
 
 pub mod course_files;
 pub mod courses;
+pub mod focus;
 pub mod grades;
 pub mod tags;
 pub mod tasks;
@@ -35,6 +37,8 @@ pub struct AppController {
     storage: Arc<dyn StorageRepository>,
     renderer: Arc<dyn PdfRenderer>,
     notes: Arc<NotesSettings>,
+    /// `None` when TimeTagger is not configured
+    time_tracker: Option<Arc<dyn TimeTracker>>,
 }
 
 impl AppController {
@@ -43,12 +47,14 @@ impl AppController {
         storage: Arc<dyn StorageRepository>,
         renderer: Arc<dyn PdfRenderer>,
         notes: NotesSettings,
+        time_tracker: Option<Arc<dyn TimeTracker>>,
     ) -> Self {
         Self {
             db,
             storage,
             renderer,
             notes: Arc::new(notes),
+            time_tracker,
         }
     }
 }
@@ -71,6 +77,8 @@ pub enum ControllerError {
     Task(#[from] TasksControllerError),
     #[error("Lecture note specific error: {0}")]
     LectureNote(#[from] LectureNotesControllerError),
+    #[error("Focus specific error: {0}")]
+    Focus(#[from] FocusControllerError),
 }
 
 /// Trims a text, `None` when it is blank
diff --git a/src/core/controller/tasks.rs b/src/core/controller/tasks.rs
index f090ce6..08b236e 100644
--- a/src/core/controller/tasks.rs
+++ b/src/core/controller/tasks.rs
@@ -12,7 +12,7 @@ use crate::core::{
         course::Course,
         course::CourseId,
         tag::TagScope,
-        task::{CalendarTask, CourseTasks, Task, TaskData, TaskId},
+        task::{CalendarTask, CourseTasks, Task, TaskData, TaskId, TodoTask},
     },
 };
 
@@ -35,6 +35,29 @@ impl super::AppController {
         Ok(calendar(tasks, &courses, from, to))
     }
 
+    /// Tasks not done of every course, with their subtasks: the ones with a deadline
+    /// first, the closest first
+    pub async fn get_todo_tasks(&self) -> Result<Vec<TodoTask>, ControllerError> {
+        let tasks = organize(self.db.get_todo_tasks().await?).tasks;
+        let courses: HashMap<_, Course> = self
+            .db
+            .get_courses()
+            .await?
+            .into_iter()
+            .map(|course| (course.id, course))
+            .collect();
+        Ok(tasks
+            .into_iter()
+            .filter_map(|task| {
+                let course = courses.get(&task.course_id)?;
+                Some(TodoTask {
+                    course: course.into(),
+                    task,
+                })
+            })
+            .collect())
+    }
+
     pub async fn get_course_tasks(
         &self,
         course_id: CourseId,
@@ -189,6 +212,7 @@ fn calendar(
             Some(CalendarTask {
                 task_id: task.id,
                 course_id: course.id,
+                course_kind: course.kind,
                 course_name: course.name.clone(),
                 course_code: course.code.clone(),
                 name: match parent {
@@ -229,6 +253,7 @@ mod tests {
     use chrono::{TimeZone, Utc};
 
     use super::*;
+    use crate::core::models::course::CourseKind;
 
     fn task(id: TaskId, parent_id: Option<TaskId>, day: Option<u32>, done: bool) -> Task {
         Task {
@@ -241,6 +266,7 @@ mod tests {
             deadline: day.map(|day| Utc.with_ymd_and_hms(2026, 10, day, 12, 0, 0).unwrap()),
             done,
             tag_ids: vec![1],
+            time_spent: 0,
             subtasks: Vec::new(),
         }
     }
@@ -264,10 +290,12 @@ mod tests {
     fn calendar_names_and_tags_subtasks_after_their_parent() {
         let course = Course {
             id: 1,
+            kind: CourseKind::Course,
             name: "OS".to_owned(),
             code: None,
             teachers: Vec::new(),
             main_page_url: None,
+            folder: "Cours/OS".to_owned(),
             slots: Vec::new(),
         };
         let from = Utc.with_ymd_and_hms(2026, 10, 1, 0, 0, 0).unwrap();
diff --git a/src/core/models/course.rs b/src/core/models/course.rs
index 79bfd3d..4efbdf2 100644
--- a/src/core/models/course.rs
+++ b/src/core/models/course.rs
@@ -5,26 +5,68 @@ use crate::core::models::time_slot::TimeSlot;
 
 pub type CourseId = i32;
 
+/// A course, or an association: both have tasks, files and slots, only the courses have
+/// teachers and grades.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
 pub struct Course {
     pub id: CourseId,
+    pub kind: CourseKind,
     /// e.g. "Advanced operating systems"
     pub name: String,
-    /// e.g. "CS-477"
+    /// e.g. "CS-477", or the acronym of an association
     pub code: Option<String>,
-    /// At least one
+    /// At least one for a course, none for an association
     pub teachers: Vec<String>,
     /// Main page of the course, usually on moodle
     pub main_page_url: Option<String>,
+    /// Folder of its files in the storage, e.g. `Cours/CS-477 Advanced operating systems`
+    pub folder: String,
     /// Weekly slots, sorted by weekday then start time
     pub slots: Vec<TimeSlot>,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
+#[serde(rename_all = "lowercase")]
+pub enum CourseKind {
+    Course,
+    Association,
+}
+
+impl CourseKind {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            CourseKind::Course => "course",
+            CourseKind::Association => "association",
+        }
+    }
+}
+
 /// Content of a course, used to create or replace one. The slots are managed apart.
 #[derive(Debug, Clone)]
 pub struct CourseData {
+    pub kind: CourseKind,
     pub name: String,
     pub code: Option<String>,
     pub teachers: Vec<String>,
     pub main_page_url: Option<String>,
 }
+
+/// What a task needs to show of its course
+#[derive(Debug, Clone, Serialize, JsonSchema)]
+pub struct CourseSummary {
+    pub id: CourseId,
+    pub kind: CourseKind,
+    pub name: String,
+    pub code: Option<String>,
+}
+
+impl From<&Course> for CourseSummary {
+    fn from(course: &Course) -> Self {
+        CourseSummary {
+            id: course.id,
+            kind: course.kind,
+            name: course.name.clone(),
+            code: course.code.clone(),
+        }
+    }
+}
diff --git a/src/core/models/course_file.rs b/src/core/models/course_file.rs
index 8429d5b..fd06943 100644
--- a/src/core/models/course_file.rs
+++ b/src/core/models/course_file.rs
@@ -7,7 +7,8 @@ use crate::core::models::{course::CourseId, tag::TagId};
 pub type CourseFileId = i32;
 
 /// A file of a course: lecture notes written in the app, or (soon) an uploaded file.
-/// Only the metadata is in the database, the content is in the storage (the NAS).
+/// Only the metadata is in the database, the content is in the storage (the NAS), in the
+/// folder of the course.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
 pub struct CourseFile {
     pub id: CourseFileId,
@@ -15,6 +16,8 @@ pub struct CourseFile {
     /// For a note, e.g. "Lecture 2 Notes: Memory subsystem", the subtitle of its pdf
     pub name: String,
     pub kind: FileKind,
+    /// Path in the folder of the course, without extension, e.g. `Notes/Lecture 1 Notes`
+    pub path: String,
     /// e.g. slides, notes
     pub tag_ids: Vec<TagId>,
     /// For a note: false when the last rendering failed
diff --git a/src/core/models/focus.rs b/src/core/models/focus.rs
new file mode 100644
index 0000000..cba6960
--- /dev/null
+++ b/src/core/models/focus.rs
@@ -0,0 +1,45 @@
+use chrono::{DateTime, Utc};
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+use crate::core::models::{course::CourseSummary, tag::TagId, task::TaskId};
+
+/// Record of TimeTagger (https://timetagger.app) counting a focus session. Kept by the
+/// client while the session runs, and sent back to stop it.
+#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
+pub struct TimetaggerRecord {
+    pub key: String,
+    /// Start, unix timestamp in seconds
+    pub t1: i64,
+    /// Description holding the tags, e.g. `#cs-477 #homework #exercise-set-3`
+    pub ds: String,
+}
+
+/// A focus session started on a task
+#[derive(Debug, Clone, Serialize, JsonSchema)]
+pub struct FocusStart {
+    pub course: CourseSummary,
+    pub task_id: TaskId,
+    pub name: String,
+    /// Name of the parent task, for a subtask
+    pub parent_name: Option<String>,
+    /// Tags of the task, or of its parent for a subtask without any
+    pub tag_ids: Vec<TagId>,
+    /// Seconds already spent on the task before this session
+    pub time_spent: i32,
+    pub started_at: DateTime<Utc>,
+    /// Whether TimeTagger is configured
+    pub timetagger_enabled: bool,
+    /// The running record, `None` when TimeTagger is not configured or failed
+    pub timetagger: Option<TimetaggerRecord>,
+    /// Why TimeTagger failed, the session runs anyway
+    pub timetagger_error: Option<String>,
+}
+
+/// End of a focus session
+#[derive(Debug, Clone, Serialize, JsonSchema)]
+pub struct FocusStop {
+    /// Seconds spent on the task, this session included
+    pub time_spent: i32,
+    pub timetagger_error: Option<String>,
+}
diff --git a/src/core/models/mod.rs b/src/core/models/mod.rs
index 9b173a4..90ec54e 100644
--- a/src/core/models/mod.rs
+++ b/src/core/models/mod.rs
@@ -1,5 +1,6 @@
 pub mod course;
 pub mod course_file;
+pub mod focus;
 pub mod grade;
 pub mod localized_string;
 pub mod tag;
diff --git a/src/core/models/tag.rs b/src/core/models/tag.rs
index ea9d654..b59b765 100644
--- a/src/core/models/tag.rs
+++ b/src/core/models/tag.rs
@@ -15,6 +15,8 @@ pub struct Tag {
     pub name: LocalizedString,
     /// Hex color used to display what is tagged, e.g. `#2563eb`
     pub color: String,
+    /// Stable name, e.g. `homework`
+    pub slug: Option<String>,
     /// What the tag can label
     pub scopes: Vec<TagScope>,
 }
diff --git a/src/core/models/task.rs b/src/core/models/task.rs
index 5db2250..1122809 100644
--- a/src/core/models/task.rs
+++ b/src/core/models/task.rs
@@ -2,7 +2,10 @@ use chrono::{DateTime, Utc};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
-use crate::core::models::{course::CourseId, tag::TagId};
+use crate::core::models::{
+    course::{CourseId, CourseKind, CourseSummary},
+    tag::TagId,
+};
 
 pub type TaskId = i32;
 
@@ -20,6 +23,8 @@ pub struct Task {
     pub deadline: Option<DateTime<Utc>>,
     pub done: bool,
     pub tag_ids: Vec<TagId>,
+    /// Seconds spent working on it, counted by the pomodoro
+    pub time_spent: i32,
     /// Sorted like the tasks. Always empty for a subtask: there is only one level.
     pub subtasks: Vec<Task>,
 }
@@ -48,6 +53,7 @@ pub struct CourseTasks {
 pub struct CalendarTask {
     pub task_id: TaskId,
     pub course_id: CourseId,
+    pub course_kind: CourseKind,
     pub course_name: String,
     pub course_code: Option<String>,
     /// Name of the task, prefixed by the one of its parent for a subtask
@@ -58,3 +64,11 @@ pub struct CalendarTask {
     /// Tags of the task, or of its parent for a subtask without any
     pub tag_ids: Vec<TagId>,
 }
+
+/// A task not done yet, with its course, for the list of the things to do
+#[derive(Debug, Clone, Serialize, JsonSchema)]
+pub struct TodoTask {
+    pub course: CourseSummary,
+    /// With all its subtasks, the ones done included
+    pub task: Task,
+}
diff --git a/src/core/repositories/course_files_repository.rs b/src/core/repositories/course_files_repository.rs
index d8675ea..a8933d3 100644
--- a/src/core/repositories/course_files_repository.rs
+++ b/src/core/repositories/course_files_repository.rs
@@ -22,14 +22,16 @@ pub trait CourseFilesRepository {
         &self,
         course_id: CourseId,
         name: String,
+        path: String,
         tag_ids: &[TagId],
     ) -> Result<CourseFile, RepositoryError>;
-    /// Sets the name and `has_pdf`, and bumps `updated_at`. `NotFound` if the note does
-    /// not exist.
+    /// Sets the name, path and `has_pdf`, and bumps `updated_at`. `NotFound` if the note
+    /// does not exist.
     async fn update_lecture_note(
         &self,
         id: CourseFileId,
         name: String,
+        path: String,
         has_pdf: bool,
     ) -> Result<CourseFile, RepositoryError>;
     /// `NotFound` if the file does not exist
diff --git a/src/core/repositories/courses_repository.rs b/src/core/repositories/courses_repository.rs
index 9c77e62..8847bc3 100644
--- a/src/core/repositories/courses_repository.rs
+++ b/src/core/repositories/courses_repository.rs
@@ -10,17 +10,22 @@ use crate::core::{
 
 #[async_trait]
 pub trait CoursesRepository {
-    /// Every course with its slots, sorted by name
+    /// Every course and association with its slots, sorted by name
     async fn get_courses(&self) -> Result<Vec<Course>, RepositoryError>;
     /// `NotFound` if the course does not exist
     async fn get_course(&self, id: CourseId) -> Result<Course, RepositoryError>;
-    /// Creates a course without any slot
-    async fn create_course(&self, course: CourseData) -> Result<Course, RepositoryError>;
-    /// Replaces the course, keeping its slots. `NotFound` if the course does not exist.
+    /// Creates a course without any slot, its files in `folder`
+    async fn create_course(
+        &self,
+        course: CourseData,
+        folder: &str,
+    ) -> Result<Course, RepositoryError>;
+    /// Replaces the course, keeping its slots and its kind. `NotFound` if the course does not exist.
     async fn update_course(
         &self,
         id: CourseId,
         course: CourseData,
+        folder: &str,
     ) -> Result<Course, RepositoryError>;
     /// Deletes the course and everything attached to it. `NotFound` if it does not exist.
     async fn delete_course(&self, id: CourseId) -> Result<(), RepositoryError>;
diff --git a/src/core/repositories/mod.rs b/src/core/repositories/mod.rs
index 2e89618..9d18b26 100644
--- a/src/core/repositories/mod.rs
+++ b/src/core/repositories/mod.rs
@@ -20,6 +20,7 @@ pub mod pdf_renderer;
 pub mod storage_repository;
 pub mod tags_repository;
 pub mod tasks_repository;
+pub mod time_tracker;
 
 /// Add every new repository trait here so the controller can use it through `db`
 #[async_trait]
diff --git a/src/core/repositories/storage_repository.rs b/src/core/repositories/storage_repository.rs
index 4acd8f1..8a64d07 100644
--- a/src/core/repositories/storage_repository.rs
+++ b/src/core/repositories/storage_repository.rs
@@ -15,4 +15,7 @@ pub trait StorageRepository: Send + Sync {
     async fn delete_file(&self, path: &str) -> Result<(), RepositoryError>;
     /// Deletes a directory and everything in it. Does nothing if it does not exist.
     async fn delete_dir(&self, path: &str) -> Result<(), RepositoryError>;
+    /// Moves a file or a directory, creating the missing parents of `to`. `NotFound` if
+    /// `from` does not exist, an error if `to` already exists.
+    async fn rename(&self, from: &str, to: &str) -> Result<(), RepositoryError>;
 }
diff --git a/src/core/repositories/tasks_repository.rs b/src/core/repositories/tasks_repository.rs
index c389292..b15e2d8 100644
--- a/src/core/repositories/tasks_repository.rs
+++ b/src/core/repositories/tasks_repository.rs
@@ -20,6 +20,9 @@ pub trait TasksRepository {
         from: DateTime<Utc>,
         to: DateTime<Utc>,
     ) -> Result<Vec<Task>, RepositoryError>;
+    /// Tasks not done of every course, with all their subtasks. Flat: `subtasks` is always
+    /// empty.
+    async fn get_todo_tasks(&self) -> Result<Vec<Task>, RepositoryError>;
     /// A single task, `subtasks` empty. `NotFound` if the task does not exist.
     async fn get_task(&self, id: TaskId) -> Result<Task, RepositoryError>;
     async fn create_task(
@@ -30,6 +33,9 @@ pub trait TasksRepository {
     ) -> Result<(), RepositoryError>;
     /// Replaces the task and its tags. `NotFound` if the task does not exist.
     async fn update_task(&self, id: TaskId, task: TaskData) -> Result<(), RepositoryError>;
+    /// Adds `seconds` to the time spent on the task, returns the new total. `NotFound` if
+    /// the task does not exist.
+    async fn add_time_spent(&self, id: TaskId, seconds: i32) -> Result<i32, RepositoryError>;
     /// Deletes the task and its subtasks. `NotFound` if the task does not exist.
     async fn delete_task(&self, id: TaskId) -> Result<(), RepositoryError>;
 }
diff --git a/src/core/repositories/time_tracker.rs b/src/core/repositories/time_tracker.rs
new file mode 100644
index 0000000..b48314c
--- /dev/null
+++ b/src/core/repositories/time_tracker.rs
@@ -0,0 +1,21 @@
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+
+use crate::core::{models::focus::TimetaggerRecord, repositories::RepositoryError};
+
+/// Where the focus sessions are also counted: TimeTagger
+#[async_trait]
+pub trait TimeTracker: Send + Sync {
+    /// Starts a running record described by `description` (text and `#tags`)
+    async fn start(
+        &self,
+        description: &str,
+        start: DateTime<Utc>,
+    ) -> Result<TimetaggerRecord, RepositoryError>;
+    /// Stops a running record at `end`
+    async fn stop(
+        &self,
+        record: &TimetaggerRecord,
+        end: DateTime<Utc>,
+    ) -> Result<(), RepositoryError>;
+}
diff --git a/src/main.rs b/src/main.rs
index 6e78ac8..6deab04 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,8 +5,14 @@ use tracing::info;
 use tracing_subscriber::{EnvFilter, layer::SubscriberExt, util::SubscriberInitExt};
 
 use crate::{
-    core::controller::{AppController, course_files::NotesSettings},
-    services::{database::SqlxDatabase, pandoc::PandocRenderer, storage::LocalStorage},
+    core::{
+        controller::{AppController, course_files::NotesSettings},
+        repositories::time_tracker::TimeTracker,
+    },
+    services::{
+        database::SqlxDatabase, pandoc::PandocRenderer, storage::LocalStorage,
+        timetagger::Timetagger,
+    },
 };
 
 mod api;
@@ -44,11 +50,21 @@ async fn main() {
             .map(|logo| template_dir.join(logo).display().to_string()),
     };
 
+    let time_tracker = config.timetagger.as_ref().map(|timetagger| {
+        let url = timetagger
+            .url
+            .as_deref()
+            .unwrap_or("https://timetagger.app/api/v2");
+        info!("Focus sessions are counted in TimeTagger ({url})");
+        Arc::new(Timetagger::new(url, timetagger.token.clone())) as Arc<dyn TimeTracker>
+    });
+
     let controller = AppController::new(
         Arc::new(Box::new(db)),
         Arc::new(LocalStorage::new(&config.storage_dir)),
         Arc::new(PandocRenderer::new(template_dir)),
         notes,
+        time_tracker,
     );
 
     // Anything that is not an api route is served from the built frontend,
diff --git a/src/services/database/course_files.rs b/src/services/database/course_files.rs
index d37b528..b09f116 100644
--- a/src/services/database/course_files.rs
+++ b/src/services/database/course_files.rs
@@ -19,6 +19,7 @@ struct CourseFileDB {
     pub course_id: i32,
     pub name: String,
     pub kind: String,
+    pub path: String,
     pub tag_ids: Vec<i32>,
     pub has_pdf: bool,
     pub created_at: DateTime<Utc>,
@@ -42,6 +43,7 @@ impl TryFrom<CourseFileDB> for CourseFile {
                     )));
                 }
             },
+            path: value.path,
             tag_ids: value.tag_ids,
             has_pdf: value.has_pdf,
             created_at: value.created_at,
@@ -62,7 +64,7 @@ impl CourseFilesRepository for SqlxDatabase {
     ) -> Result<Vec<CourseFile>, RepositoryError> {
         query_as!(
             CourseFileDB,
-            r#"SELECT f.id, f.course_id, f.name, f.kind, f.has_pdf, f.created_at, f.updated_at,
+            r#"SELECT f.id, f.course_id, f.name, f.kind, f.path, f.has_pdf, f.created_at, f.updated_at,
                       COALESCE(ARRAY_AGG(ft.tag_id ORDER BY ft.tag_id)
                                FILTER (WHERE ft.tag_id IS NOT NULL), '{}') AS "tag_ids!"
                FROM course_files f
@@ -82,7 +84,7 @@ impl CourseFilesRepository for SqlxDatabase {
     async fn get_course_file(&self, id: CourseFileId) -> Result<CourseFile, RepositoryError> {
         query_as!(
             CourseFileDB,
-            r#"SELECT f.id, f.course_id, f.name, f.kind, f.has_pdf, f.created_at, f.updated_at,
+            r#"SELECT f.id, f.course_id, f.name, f.kind, f.path, f.has_pdf, f.created_at, f.updated_at,
                       COALESCE(ARRAY_AGG(ft.tag_id ORDER BY ft.tag_id)
                                FILTER (WHERE ft.tag_id IS NOT NULL), '{}') AS "tag_ids!"
                FROM course_files f
@@ -101,14 +103,16 @@ impl CourseFilesRepository for SqlxDatabase {
         &self,
         course_id: CourseId,
         name: String,
+        path: String,
         tag_ids: &[TagId],
     ) -> Result<CourseFile, RepositoryError> {
         let mut tx = self.pool.begin().await?;
         let id = query!(
-            r#"INSERT INTO course_files (course_id, name, kind) VALUES ($1, $2, 'note')
+            r#"INSERT INTO course_files (course_id, name, kind, path) VALUES ($1, $2, 'note', $3)
                RETURNING id"#,
             course_id,
             name,
+            path,
         )
         .fetch_one(&mut *tx)
         .await?
@@ -129,13 +133,15 @@ impl CourseFilesRepository for SqlxDatabase {
         &self,
         id: CourseFileId,
         name: String,
+        path: String,
         has_pdf: bool,
     ) -> Result<CourseFile, RepositoryError> {
         let result = query!(
-            r#"UPDATE course_files SET name = $2, has_pdf = $3, updated_at = now()
+            r#"UPDATE course_files SET name = $2, path = $3, has_pdf = $4, updated_at = now()
                WHERE id = $1 AND kind = 'note'"#,
             id,
             name,
+            path,
             has_pdf,
         )
         .execute(&self.pool)
diff --git a/src/services/database/courses.rs b/src/services/database/courses.rs
index 619e52f..eead831 100644
--- a/src/services/database/courses.rs
+++ b/src/services/database/courses.rs
@@ -10,7 +10,7 @@ use sqlx::{PgExecutor, query, query_as};
 use crate::{
     core::{
         models::{
-            course::{Course, CourseData, CourseId},
+            course::{Course, CourseData, CourseId, CourseKind},
             time_slot::{TimeSlot, TimeSlotData, TimeSlotId},
         },
         repositories::{RepositoryError, courses_repository::CoursesRepository},
@@ -20,22 +20,34 @@ use crate::{
 
 struct CourseDB {
     pub id: i32,
+    pub kind: String,
     pub name: String,
     pub code: Option<String>,
     pub teachers: Vec<String>,
     pub main_page_url: Option<String>,
+    pub folder: String,
 }
 
 impl CourseDB {
-    fn with_slots(self, slots: Vec<TimeSlot>) -> Course {
-        Course {
+    fn with_slots(self, slots: Vec<TimeSlot>) -> Result<Course, RepositoryError> {
+        Ok(Course {
             id: self.id,
+            kind: match self.kind.as_str() {
+                "course" => CourseKind::Course,
+                "association" => CourseKind::Association,
+                kind => {
+                    return Err(RepositoryError::TypeConversion(format!(
+                        "invalid course kind {kind}"
+                    )));
+                }
+            },
             name: self.name,
             code: self.code,
             teachers: self.teachers,
             main_page_url: self.main_page_url,
+            folder: self.folder,
             slots,
-        }
+        })
     }
 }
 
@@ -87,7 +99,8 @@ impl CoursesRepository for SqlxDatabase {
     async fn get_courses(&self) -> Result<Vec<Course>, RepositoryError> {
         let courses = query_as!(
             CourseDB,
-            r#"SELECT id, name, code, teachers, main_page_url FROM courses ORDER BY name, id"#
+            r#"SELECT id, kind, name, code, teachers, main_page_url, folder
+               FROM courses ORDER BY name, id"#
         )
         .fetch_all(&self.pool)
         .await?;
@@ -108,65 +121,75 @@ impl CoursesRepository for SqlxDatabase {
                 .push(slot.try_into()?);
         }
 
-        Ok(courses
+        courses
             .into_iter()
             .map(|course| {
                 let slots = slots_by_course.remove(&course.id).unwrap_or_default();
                 course.with_slots(slots)
             })
-            .collect())
+            .collect()
     }
 
     async fn get_course(&self, id: CourseId) -> Result<Course, RepositoryError> {
         let row = query_as!(
             CourseDB,
-            r#"SELECT id, name, code, teachers, main_page_url FROM courses WHERE id = $1"#,
+            r#"SELECT id, kind, name, code, teachers, main_page_url, folder
+               FROM courses WHERE id = $1"#,
             id,
         )
         .fetch_optional(&self.pool)
         .await?
         .ok_or_else(|| RepositoryError::NotFound(format!("course {id}")))?;
         let slots = get_slots(&self.pool, id).await?;
-        Ok(row.with_slots(slots))
+        row.with_slots(slots)
     }
 
-    async fn create_course(&self, course: CourseData) -> Result<Course, RepositoryError> {
+    async fn create_course(
+        &self,
+        course: CourseData,
+        folder: &str,
+    ) -> Result<Course, RepositoryError> {
         let row = query_as!(
             CourseDB,
-            r#"INSERT INTO courses (name, code, teachers, main_page_url)
-               VALUES ($1, $2, $3, $4)
-               RETURNING id, name, code, teachers, main_page_url"#,
+            r#"INSERT INTO courses (kind, name, code, teachers, main_page_url, folder)
+               VALUES ($1, $2, $3, $4, $5, $6)
+               RETURNING id, kind, name, code, teachers, main_page_url, folder"#,
+            course.kind.as_str(),
             course.name,
             course.code,
             &course.teachers,
             course.main_page_url,
+            folder,
         )
         .fetch_one(&self.pool)
         .await?;
-        Ok(row.with_slots(Vec::new()))
+        row.with_slots(Vec::new())
     }
 
     async fn update_course(
         &self,
         id: CourseId,
         course: CourseData,
+        folder: &str,
     ) -> Result<Course, RepositoryError> {
         let row = query_as!(
             CourseDB,
-            r#"UPDATE courses SET name = $2, code = $3, teachers = $4, main_page_url = $5
+            r#"UPDATE courses
+               SET name = $2, code = $3, teachers = $4, main_page_url = $5, folder = $6
                WHERE id = $1
-               RETURNING id, name, code, teachers, main_page_url"#,
+               RETURNING id, kind, name, code, teachers, main_page_url, folder"#,
             id,
             course.name,
             course.code,
             &course.teachers,
             course.main_page_url,
+            folder,
         )
         .fetch_optional(&self.pool)
         .await?
         .ok_or_else(|| RepositoryError::NotFound(format!("course {id}")))?;
         let slots = get_slots(&self.pool, id).await?;
-        Ok(row.with_slots(slots))
+        row.with_slots(slots)
     }
 
     async fn delete_course(&self, id: CourseId) -> Result<(), RepositoryError> {
diff --git a/src/services/database/tags.rs b/src/services/database/tags.rs
index 703cded..652dbda 100644
--- a/src/services/database/tags.rs
+++ b/src/services/database/tags.rs
@@ -14,6 +14,7 @@ struct TagDB {
     pub id: i32,
     pub name: Value,
     pub color: String,
+    pub slug: Option<String>,
     pub scopes: Vec<String>,
 }
 
@@ -36,6 +37,7 @@ impl TryFrom<TagDB> for Tag {
             id: value.id,
             name: serde_json::from_value(value.name)?,
             color: value.color,
+            slug: value.slug,
             scopes: value
                 .scopes
                 .iter()
@@ -50,7 +52,7 @@ impl TagsRepository for SqlxDatabase {
     async fn get_tags(&self, scope: Option<TagScope>) -> Result<Vec<Tag>, RepositoryError> {
         query_as!(
             TagDB,
-            r#"SELECT id, name, color, scopes FROM tags
+            r#"SELECT id, name, color, slug, scopes FROM tags
                WHERE $1::TEXT IS NULL OR $1 = ANY(scopes)
                ORDER BY id"#,
             scope.map(TagScope::as_str),
diff --git a/src/services/database/tasks.rs b/src/services/database/tasks.rs
index 8e1fe2d..5f4666f 100644
--- a/src/services/database/tasks.rs
+++ b/src/services/database/tasks.rs
@@ -26,6 +26,7 @@ struct TaskDB {
     pub links: Vec<String>,
     pub deadline: Option<DateTime<Utc>>,
     pub done: bool,
+    pub time_spent: i32,
     pub tag_ids: Vec<i32>,
 }
 
@@ -41,6 +42,7 @@ impl From<TaskDB> for Task {
             deadline: value.deadline,
             done: value.done,
             tag_ids: value.tag_ids,
+            time_spent: value.time_spent,
             subtasks: Vec::new(),
         }
     }
@@ -73,7 +75,7 @@ impl TasksRepository for SqlxDatabase {
         Ok(query_as!(
             TaskDB,
             r#"SELECT t.id, t.course_id, t.parent_id, t.name, t.description, t.links,
-                      t.deadline, t.done,
+                      t.deadline, t.done, t.time_spent,
                       COALESCE(ARRAY_AGG(tt.tag_id ORDER BY tt.tag_id)
                                FILTER (WHERE tt.tag_id IS NOT NULL), '{}') AS "tag_ids!"
                FROM tasks t
@@ -98,7 +100,7 @@ impl TasksRepository for SqlxDatabase {
         Ok(query_as!(
             TaskDB,
             r#"SELECT t.id, t.course_id, t.parent_id, t.name, t.description, t.links,
-                      t.deadline, t.done,
+                      t.deadline, t.done, t.time_spent,
                       COALESCE(ARRAY_AGG(tt.tag_id ORDER BY tt.tag_id)
                                FILTER (WHERE tt.tag_id IS NOT NULL), '{}') AS "tag_ids!"
                FROM tasks t
@@ -118,11 +120,32 @@ impl TasksRepository for SqlxDatabase {
         .collect())
     }
 
+    async fn get_todo_tasks(&self) -> Result<Vec<Task>, RepositoryError> {
+        Ok(query_as!(
+            TaskDB,
+            r#"SELECT t.id, t.course_id, t.parent_id, t.name, t.description, t.links,
+                      t.deadline, t.done, t.time_spent,
+                      COALESCE(ARRAY_AGG(tt.tag_id ORDER BY tt.tag_id)
+                               FILTER (WHERE tt.tag_id IS NOT NULL), '{}') AS "tag_ids!"
+               FROM tasks t
+               LEFT JOIN task_tags tt ON tt.task_id = t.id
+               WHERE t.id IN (SELECT id FROM tasks WHERE parent_id IS NULL AND NOT done)
+                  OR t.parent_id IN (SELECT id FROM tasks WHERE parent_id IS NULL AND NOT done)
+               GROUP BY t.id
+               ORDER BY t.id"#,
+        )
+        .fetch_all(&self.pool)
+        .await?
+        .into_iter()
+        .map(Into::into)
+        .collect())
+    }
+
     async fn get_task(&self, id: TaskId) -> Result<Task, RepositoryError> {
         query_as!(
             TaskDB,
             r#"SELECT t.id, t.course_id, t.parent_id, t.name, t.description, t.links,
-                      t.deadline, t.done,
+                      t.deadline, t.done, t.time_spent,
                       COALESCE(ARRAY_AGG(tt.tag_id ORDER BY tt.tag_id)
                                FILTER (WHERE tt.tag_id IS NOT NULL), '{}') AS "tag_ids!"
                FROM tasks t
@@ -189,6 +212,19 @@ impl TasksRepository for SqlxDatabase {
         Ok(())
     }
 
+    async fn add_time_spent(&self, id: TaskId, seconds: i32) -> Result<i32, RepositoryError> {
+        query!(
+            r#"UPDATE tasks SET time_spent = time_spent + $2 WHERE id = $1
+               RETURNING time_spent"#,
+            id,
+            seconds,
+        )
+        .fetch_optional(&self.pool)
+        .await?
+        .map(|row| row.time_spent)
+        .ok_or_else(|| not_found(id))
+    }
+
     async fn delete_task(&self, id: TaskId) -> Result<(), RepositoryError> {
         // The subtasks and the tags are removed by the `ON DELETE CASCADE`
         let result = query!("DELETE FROM tasks WHERE id = $1", id)
diff --git a/src/services/mod.rs b/src/services/mod.rs
index 29e2ed1..ffb7c35 100644
--- a/src/services/mod.rs
+++ b/src/services/mod.rs
@@ -3,3 +3,4 @@
 pub mod database;
 pub mod pandoc;
 pub mod storage;
+pub mod timetagger;
diff --git a/src/services/storage.rs b/src/services/storage.rs
index 9e1a6bf..aac8ce6 100644
--- a/src/services/storage.rs
+++ b/src/services/storage.rs
@@ -75,4 +75,30 @@ impl StorageRepository for LocalStorage {
             _ => Ok(()),
         }
     }
+
+    async fn rename(&self, from: &str, to: &str) -> Result<(), RepositoryError> {
+        let source = self.resolve(from)?;
+        let target = self.resolve(to)?;
+        if !fs::try_exists(&source)
+            .await
+            .map_err(|err| io_error(from, err))?
+        {
+            return Err(RepositoryError::NotFound(format!("file {from}")));
+        }
+        // `rename` would silently replace a file
+        if fs::try_exists(&target)
+            .await
+            .map_err(|err| io_error(to, err))?
+        {
+            return Err(RepositoryError::Internal(format!("{to} already exists")));
+        }
+        if let Some(parent) = target.parent() {
+            fs::create_dir_all(parent)
+                .await
+                .map_err(|err| io_error(to, err))?;
+        }
+        fs::rename(source, target)
+            .await
+            .map_err(|err| io_error(from, err))
+    }
 }
diff --git a/src/services/timetagger.rs b/src/services/timetagger.rs
new file mode 100644
index 0000000..074fcbb
--- /dev/null
+++ b/src/services/timetagger.rs
@@ -0,0 +1,135 @@
+//! Client of the TimeTagger api (https://timetagger.app/api_docs). A record is running
+//! while its start `t1` equals its end `t2`: it is created that way, then written again
+//! with its end to stop it.
+
+use std::{
+    hash::{BuildHasher, RandomState},
+    time::{Duration, SystemTime},
+};
+
+use async_trait::async_trait;
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+
+use crate::core::{
+    models::focus::TimetaggerRecord,
+    repositories::{RepositoryError, time_tracker::TimeTracker},
+};
+
+const TIMEOUT: Duration = Duration::from_secs(10);
+
+pub struct Timetagger {
+    client: reqwest::Client,
+    /// e.g. `https://timetagger.app/api/v2`
+    url: String,
+    token: String,
+}
+
+impl Timetagger {
+    pub fn new(url: &str, token: String) -> Self {
+        Self {
+            client: reqwest::Client::builder()
+                .timeout(TIMEOUT)
+                .build()
+                .expect("Unable to build the http client"),
+            url: url.trim_end_matches('/').to_owned(),
+            token,
+        }
+    }
+
+    async fn put(&self, record: Record<'_>) -> Result<(), RepositoryError> {
+        let response = self
+            .client
+            .put(format!("{}/records", self.url))
+            .header("authtoken", &self.token)
+            .json(&[record])
+            .send()
+            .await
+            .map_err(|err| RepositoryError::Internal(format!("TimeTagger unreachable: {err}")))?;
+        let status = response.status();
+        if !status.is_success() {
+            let body = response.text().await.unwrap_or_default();
+            return Err(RepositoryError::Internal(format!(
+                "TimeTagger answered {status}: {body}"
+            )));
+        }
+        let result: PutResult = response.json().await.map_err(|err| {
+            RepositoryError::Internal(format!("Unexpected answer of TimeTagger: {err}"))
+        })?;
+        if !result.failed.is_empty() {
+            return Err(RepositoryError::Internal(format!(
+                "TimeTagger refused the record: {}",
+                result.errors.join(", ")
+            )));
+        }
+        Ok(())
+    }
+}
+
+#[derive(Serialize)]
+struct Record<'a> {
+    key: &'a str,
+    t1: i64,
+    t2: i64,
+    ds: &'a str,
+    /// Modification time
+    mt: i64,
+    /// Server time, set by the server
+    st: f64,
+}
+
+#[derive(Deserialize)]
+struct PutResult {
+    #[serde(default)]
+    failed: Vec<String>,
+    #[serde(default)]
+    errors: Vec<String>,
+}
+
+/// Unique enough key for a record
+fn random_key() -> String {
+    format!("{:016x}", RandomState::new().hash_one(SystemTime::now()))
+}
+
+#[async_trait]
+impl TimeTracker for Timetagger {
+    async fn start(
+        &self,
+        description: &str,
+        start: DateTime<Utc>,
+    ) -> Result<TimetaggerRecord, RepositoryError> {
+        let key = random_key();
+        let t1 = start.timestamp();
+        self.put(Record {
+            key: &key,
+            t1,
+            t2: t1,
+            ds: description,
+            mt: Utc::now().timestamp(),
+            st: 0.0,
+        })
+        .await?;
+        Ok(TimetaggerRecord {
+            key,
+            t1,
+            ds: description.to_owned(),
+        })
+    }
+
+    async fn stop(
+        &self,
+        record: &TimetaggerRecord,
+        end: DateTime<Utc>,
+    ) -> Result<(), RepositoryError> {
+        self.put(Record {
+            key: &record.key,
+            t1: record.t1,
+            // A record of zero second would stay running
+            t2: end.timestamp().max(record.t1 + 1),
+            ds: &record.ds,
+            mt: Utc::now().timestamp(),
+            st: 0.0,
+        })
+        .await
+    }
+}
diff --git a/src/utils/config.rs b/src/utils/config.rs
index 7e6d248..4558eed 100644
--- a/src/utils/config.rs
+++ b/src/utils/config.rs
@@ -30,16 +30,27 @@ pub struct NotesConfig {
     pub student_id: Option<String>,
 }
 
+/// TimeTagger account the focus sessions are counted in
+#[derive(Deserialize, Clone)]
+pub struct TimetaggerConfig {
+    /// Api of the TimeTagger server, `https://timetagger.app/api/v2` by default
+    pub url: Option<String>,
+    /// Api token, from the account page of TimeTagger
+    pub token: String,
+}
+
 #[derive(Deserialize, Clone)]
 pub struct AppConfig {
     pub server: ServerConfig,
     pub postgres: PostgresConfig,
     /// Directory containing the built frontend
     pub frontend_dir: String,
-    /// Where the files of the courses are stored (lecture notes, pdf...). A local
-    /// directory standing in for the NAS for now.
+    /// Where the files of the courses and associations are stored (lecture notes,
+    /// pdf...), one folder each. A local directory standing in for the NAS for now.
     pub storage_dir: String,
     pub notes: NotesConfig,
+    /// Optional: without it the pomodoro only counts the time in the app
+    pub timetagger: Option<TimetaggerConfig>,
 }
 
 impl AppConfig {