Online MIDI tester

Allow MIDI access, then play. Every message arrives in a live log with channel, note and value.

Devices

    Message log

    1. Waiting for MIDI messages

    How to run this test

    1. Use a browser that supports Web MIDI, such as Chrome or Edge.
    2. Connect your MIDI device and press Connect MIDI.
    3. Allow access when the browser asks.
    4. Play notes, move faders and turn knobs to see each message.

    How to read the result

    Note messages
    Note on and note off with the note number and velocity. A key that sends velocity 127 no matter how softly you press may have a sensor fault or a fixed velocity setting.
    Control change
    Knobs and faders send a controller number and a value from 0 to 127. A value that jumps or skips while you turn slowly points to a dirty potentiometer.

    Questions about this test

    Why is my MIDI device not listed?
    Close other music software that may hold the device, reconnect it, then press Connect MIDI again. Safari does not support Web MIDI.
    Is MIDI data sent anywhere?
    No. Messages are only shown on this page and are cleared when you leave.