Audio Waveform Editor & Loudness Analyzer
Files & media Local only
MIDI Piano Roll Editor
Local MIDI arrangementOpen, edit, audition, quantize and export Standard MIDI files in a visual browser piano roll.
Arrange a Standard MIDI file
Open a MIDI file, create a blank project or use the example to edit notes, tracks, timing, velocity and tempo in a visual piano roll.
MIDI and playback stay local
Parsing, transformations, lightweight oscillator audition and serialization run entirely in this browser.
How to use it
- 01
Open or create a MIDI project
Parse a bounded Standard MIDI file, start blank, or load a generated multitrack sketch.
- 02
Arrange and audition
Edit tracks and note events in a zoomable piano roll, then audition selected tracks with lightweight browser synthesis and loop controls.
- 03
Transform and export
Quantize timing, transpose pitch, scale velocity or length, and export a valid MIDI file, note CSV or project JSON.
Frequently asked questions
Does playback use the MIDI instruments?
Playback uses a lightweight Web Audio oscillator preview, not a full General MIDI sound bank. Instrument and channel metadata remain in the exported MIDI.
What MIDI format is exported?
The Tone.js MIDI serializer writes a Standard MIDI file from the current tempo, track and event model.
Is the MIDI uploaded?
No. Parsing, editing, preview synthesis and export run locally in the browser.
Are very large files supported?
The parser enforces file and event budgets so malicious or orchestral-scale inputs cannot freeze a static browser page.
Related tools
Keep working with other focused browser utilities.