Piano Improvisation Helper
A small app for the moment you want to play along with a song and don't know what key it's in.
Independent development. React, TypeScript, Web Audio and pitch-class analysis.
Search for the song. If there's an audio preview, the browser decodes the clip, builds a pitch-class histogram across frames, and ranks major and minor keys against it. No server involved.
Microphone recognition is still a placeholder, so search is the path that works, and the alternates stay visible because the estimate is only as good as the clip.
State
Search and preview analysis work end to end. The key it gives you is an estimate from the preview, which is why it shows more than one.