Hypate MIDI Generator v · free · runs in your browser · no install

This page is a self-contained, procedural music-theory engine: scales and modes, generic functional-harmony progressions, rhythm templates, simple voice leading, a seeded random number generator. There is no cloud model, no neural network, no training corpus, and nothing is copied from existing songs. Every note is placed by rules, from the seed you typed, so a clip is reproducible by anyone with the same settings. The preview sound is a small browser synth (a pad, a bass, a plucked lead); it is there so you can hear the harmony, not to sound finished. The .mid file is the product, and it sounds like whatever instruments you give it in your DAW.

Output: Standard MIDI File type 1, 480 PPQ, 4/4, three tracks (Chords, Bass, Motif) plus tempo and key info. Files are named mood_key_bars_bpm_seed.mid. Nothing leaves your computer; this page makes no network requests, so it also works offline: save the page (or download index.html from GitHub) and open it from your disk.