Is there a Youtube API that gives only audio? [closed]

Answer 1

Regarding the Terms of Service of the YouTube API

https://developers.google.com/youtube/terms/developer-policies

YOU CAN'T :

separate, isolate, or modify the audio or video components of any YouTube audiovisual content made available through the YouTube API;

promote separately the audio or video components of any YouTube audiovisual content made available through the YouTube API;