Your files stay on your device
MIDI monitor
Connect a MIDI keyboard or controller and watch the notes come in.
requestMIDIAccess({ sysex: false }) · note/CC table · teardown removes every listener
Connect attaches this page to your MIDI inputs. The browser may prompt for access on the press. Play notes or move CC knobs on a connected controller and the messages appear in the table below, decoded.
- requestMIDIAccess({ sysex: false }); system-exclusive messages are never requested, so this page cannot send or receive device firmware data even if a device offers it.
- Chromium prompts for MIDI on first access; Firefox keeps a setting. Denied or unavailable states are named, never retried behind your back.
- Stop removes every input listener and drops the access object. MIDI inputs themselves are owned by the browser, not this page; closing the page can never leave a port 'held'.
- Messages live in this page’s memory, capped at 120 rows: Stop or navigation clears them.
Paste, drop, or type to begin. Everything stays on this device.