Building a Chord Progression Generator in the Browser — Music Theory in JS, Sound via Web Audio API

Pop songs, jazz turnarounds, Pachelbel's canon. Chord progressions you've heard a thousand times all reduce to scale degrees stacked on a diatonic scale. This tool generates progressions in 12 keys × 2 scales × 7 genre presets and plays them through the Web Audio API. ~300 lines of vanilla JS, zero dependencies.

🌐 Demo:

(try the Pachelbel preset in C major with 7ths on)