PyTheory Playground

Earlier this spring I wrote a few essays about PyTheory, the music theory library I was stuck on for five years and finally unstuck. The short version: it models tones, scales, chords, and fretboards in Python the way a musician actually thinks about them, it grew into a mini DAW with a NumPy synthesizer inside, and I used it to write an album. It hasn't slowed down since. The library that rendered that album has since learned to transcribe audio, engrave sheet music with LilyPond, tune a guitar in real time, and sync its clock with Ableton. But everything it can do has lived behind one gate: pip install pytheory. For a programmer, that's not a gate at all. For everyone else, it's the whole wall. So the library has a front door now. It's called PyTheory Playground, it runs in your browser, and there is nothing to install. You pick a chord and watch the fingering appear. You hum a melody and get it back harmonized. You tune your guitar against a strobe. Every result on every page is…