midee - free online MIDI player and Synthesia alternative

midee is a free, open-source online MIDI player, visualizer, and practice app that runs entirely in your browser. Drop a .mid file and it plays on a full 88-key piano roll with cascading notes, glow halos, and particle bursts - a Synthesia-style piano-roll visualizer, but web-native, design-forward, and free.

It's also a live MIDI instrument and a simple loop station. Plug in a MIDI keyboard (Web MIDI), or play from your laptop keyboard, and jam. Loop a phrase bar-snapped to the metronome, layer takes, record a session, and export the result as a frame-accurate 1080p MP4 with audio baked in.

midee requires JavaScript. Please enable JavaScript to use the app.

What midee does

Play MIDI files in the browser - multi-track, per-track color, full 88 keys.
Live MIDI play from Web MIDI controllers or your laptop keyboard (FL Studio layout).
Learn mode - play-along wait mode, sight reading, interval training, accuracy, streaks, and weak-note practice.
Loop station - bar-snapped to the metronome, layerable, undo stack, export as .mid.
Session recording - capture a live performance and bounce to .mid or video.
MP4 export - 720p, 1080p, vertical (TikTok, Reels), square, or native. Frame-accurate, audio baked in, rendered locally via WebCodecs.
Themes, instruments, particles - five themes, sampled piano plus multiple synth and acoustic voices, cycleable particle styles.
Free and open source - 100% client-side, no upload, no account, no watermark.

Who midee is for

Bedroom producers who want a quick piano-roll video for a Reel or YouTube Short. Piano learners who want to visualize a new piece. Classical music fans who want to turn a MIDI from the Mutopia project into a shareable clip. MIDI keyboard owners who want something beautiful to look at while they jam, without firing up a full DAW.

How midee compares

If you've looked at Synthesia (native piano learning), SeeMusic (paid video visualization), sightread.dev (focused browser practice), or MIDIano / midi2vidi (simple MIDI tools), midee is the web-native, open-source alternative - with MIDI playback, live mode, Learn mode, looping, recording, and frame-accurate MP4 export in one place.

Common questions

Is it really free? Yes. No account, no paywall, no watermark.

Does my MIDI get uploaded? No. Everything runs in your browser. Your .mid and the rendered MP4 never leave the machine.

Can I use my MIDI keyboard? Yes - any Web MIDI-compatible controller works. Your laptop keyboard works too.

What do I need to run it? A recent Chromium browser (Chrome 94+), Safari 16.4+, or Firefox 130+. Desktop recommended; iPad works; phone is limited.

Open source on GitHub - contributions welcome.