The server grabs the audio from the post and fingerprints it.

Records up to 30 s (auto-stops) — about 10 s of clear audio works best.

Grabs the best audio track YouTube offers — the original stream, untouched (no re-encoding) — and gives you a temporary download link.

Works with any site yt-dlp supports — TikTok, X/Twitter, Facebook, Vimeo, Twitch, … — and gives you a temporary download link.