Free · Private · No upload

MIDI Tools

Open any MIDI file to play it, visualize the piano roll, transpose notes, change BPM and mute tracks — all in your browser.

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Drop a MIDI file here or click to open
.mid · .midi · Processed 100% in your browser — never uploaded

Open, visualize, and edit MIDI files — no DAW required

Most MIDI tools either require a DAW installation (Logic, Ableton, FL Studio), a plugin, or uploading your file to a third-party server. This tool runs entirely in your browser using the Web Audio API — no software to install, no files uploaded anywhere.

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Piano roll visualizer

See your MIDI file as a piano roll — color-coded by track, with the correct piano keyboard on the left. Zoom in to inspect individual notes or zoom out for the full picture.

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Transpose in one click

Shift all notes up or down by any number of semitones. The modified MIDI is re-encoded in your browser and downloads instantly — the original file is never touched.

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Track control

See which instruments are on each track, mute individual tracks for playback, and check note counts. Useful for separating a melody from accompaniment.

Frequently Asked Questions

Can I play a MIDI file without installing anything?

Yes. Drop your .mid file and click Play. The browser generates audio using oscillator synthesis via the Web Audio API — no plugins, no software, no upload.

How does transposing work?

On the Transpose tab, set the number of semitones to shift (positive = higher, negative = lower). The tool patches the note bytes in the original MIDI binary and lets you download the result. All other MIDI data (timing, controllers, sysex) is preserved exactly.

Can I change the tempo / BPM?

Yes. On the Transpose tab you can also set a new BPM. The tool patches all tempo meta events in the MIDI file.

What MIDI formats are supported?

MIDI format 0 (single track), format 1 (multi-track, the most common), and format 2 (multi-song). Files must have the .mid or .midi extension.

Why does the sound use simple oscillators instead of real instruments?

Loading a full General MIDI soundfont in the browser takes 50–150MB. For a quick preview tool, oscillator synthesis is much faster. For production-quality playback, open the file in a DAW or use a standalone MIDI player with soundfonts.