Is it perfect? No. Scripts break. YouTube fights back. But for the savvy user who wants offline access to tutorials, music, or personal vlogs, this is the most elegant solution available today.
| Issue | Likely Fix | |-------|-------------| | Buttons don't appear | YouTube layout changed; update the selector ( #top-level-buttons-computed ) | | Download fails / 403 error | The stream URL expired; refresh page and click again quickly | | Audio is not MP3 | YouTube serves M4A; rename or convert with FFmpeg/VLC | | Video has no audio | Script picks video-only stream; you'll need to merge audio+video separately (advanced) | | "Failed to fetch video info" | YouTube API key may be outdated; search for a fresh youtubei/v1/player key online | local youtube downloader tampermonkey
async function fetchStreams(videoId, type, videoTitle) const apiUrl = `https://www.youtube.com/youtubei/v1/player?key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8`; const data = videoId: videoId, context: client: clientName: "WEB", clientVersion: "2.20230101.00.00" Is it perfect
)();
By combining a local YouTube downloader with TamperMonkey, you can enjoy the following benefits: YouTube fights back