v1.0 Tools < 100 KB Google Chrome or Microsoft Edge (Web MIDI API)
MidiSpy — Browser-based MIDI Monitor
Free browser-based MIDI monitoring tool. See every incoming MIDI message in real time — notes, CCs, pitch bend, SysEx, and clock. No install required.
Get MidiSpy — Browser-based MIDI Monitor for free
Open the file in Chrome or Edge, grant MIDI access, and every incoming MIDI message from your connected devices shows up in real time. That’s it — no install, no server, no internet connection.
What’s included:
- Single HTML file — drag into browser and go
- Works with USB-MIDI, MIDI interfaces, and virtual ports (e.g. from your DAW)
Key features:
- Real-time log: notes, CC, program change, pitch bend, SysEx, MIDI clock
- Per-message-type filter checkboxes
- Per-port mute (devices auto-detected, hot-plug supported)
- Color-coded HEX + binary display of every byte
- 150-entry rolling log to keep things snappy
- 100% local — no MIDI data ever leaves your browser