{
  "$type": "site.standard.document",
  "canonicalUrl": "https://devlog.croft.click/2026/05/11/tourmaline-web-worker",
  "description": "Moved the entire analysis pipeline from server-side POST to a browser web worker, fixing Vercel body size limits for large scrobble histories",
  "path": "/2026/05/11/tourmaline-web-worker",
  "publishedAt": "2026-05-11T09:50:00.000Z",
  "site": "at://did:plc:ofrbh253gwicbkc5nktqepol/site.standard.publication/3mlen2qhzrt2s",
  "tags": [
    "atproto",
    "pkgs",
    "music",
    "typescript"
  ],
  "textContent": "Analysis pipeline moved from server-side computation to a web worker. The previous approach POSTed scrobbles to /api/profile/[did], but Vercel's 4.5MB serverless function body limit meant users with 50K+ scrobbles (~8.5MB JSON) got silently empty profiles.\n\nThe web worker runs the full pipeline (Aggregator, genre/mood/era/timeline profiling, diversity, obscurity, sessions, personality, story recap) off the main thread. Scrobbles pass from client memory to the worker via structured clone — no network round-trip, no body size limits. The worker bundle is 56KB. Client strips scrobbles to essential fields (playedTime, trackName, releaseName, artists[0].name, duration, musicServiceBaseDomain) before posting to the worker.\n\nTwo dead ends preceded this: first, a GET endpoint that relied on server-side SQLite cache (ephemeral on Vercel — each serverless invocation gets a fresh filesystem), then a POST endpoint that hit the body limit. The worker is the right architecture — the data is already in the browser, the computation is pure, and there are no deployment constraints.",
  "title": "Tourmaline: analysis moves to web worker"
}