You want the transcripts of a whole YouTube channel: to feed a RAG pipeline, summarise talks with an LLM, or count how often a topic comes up. The obvious first stop is the official YouTube Data API. It won't get you there. This post covers why, what the free DIY route looks like, and how to do it in bulk with one API call.

Disclosure: I built the YouTube Transcript & Subtitles Scraper on Apify that the last part uses. The numbers below come from real runs of it.

Why the YouTube Data API doesn't work for this

The Data API has a captions resource, so it looks like the right tool. But the captions.download reference says the method needs OAuth with the youtube.force-ssl or youtubepartner scope, and the user has to have permission to edit the video.…