yt.wker.dev — YouTube transcripts for AI agents. Free, no key.

Swap the domain of any YouTube link:
  https://www.youtube.com/watch?v=VIDEO_ID  →  https://yt.wker.dev/watch?v=VIDEO_ID
  https://youtu.be/VIDEO_ID                 →  https://yt.wker.dev/VIDEO_ID
(shorts/, live/, embed/ paths work the same way)

Options (query string):
  ts=1       prefix each line with [mm:ss]
  lang=th    pick a caption language (default: the video's own / first manual track)

Returns plain text: a short header (title, channel, length, caption track), a blank line, then the transcript.
Captions are YouTube's own tracks; auto-captions ("auto") have no punctuation.
A 503 means YouTube refused this call (bot check) — retry after a few seconds.

Agents: call it with curl (or any HTTP GET), e.g.
  curl -s "https://yt.wker.dev/watch?v=dQw4w9WgXcQ"
If you run in the claude.ai sandbox and the call is blocked, the user must allow the domain once:
  Settings → Capabilities → (bottom) Domain allowlist → choose "All domains",
  or add  yt.wker.dev  to "Additional allowed domains".