MIDI Device Test
List MIDI inputs and outputs, their connection state and manufacturer info, reacting to connect/disconnect.
How this test works
MIDI tests use the Web MIDI API to list your connected devices and stream their messages. When you grant access, the browser hands us the inputs and outputs; we attach a listener that receives each raw MIDI message with a timestamp.
We parse those bytes into musical events — note on/off with velocity, control changes such as sustain (CC64), pitch bend, and program changes — and display them on a piano and in a log. Nothing is sent anywhere; parsing happens locally.
Access is requested only when you click, and the page stays useful even where Web MIDI is unavailable by explaining support and offering guidance.
How to use it
- Connect your MIDI device by USB or through a MIDI interface.
- Press the grant-access button and allow MIDI access.
- Confirm your device appears in the inputs list.
- Play notes, move controls, or press the sustain pedal and watch the events appear.
- Use the log’s filter, clear and download options to inspect the message stream.
What it detects
- Connected MIDI inputs and outputs and their connection state
- Note on/off events with velocity and channel
- Control changes (including sustain), pitch bend and program changes
- Manufacturer and device name where the browser provides them
What it can’t detect
- Anything on browsers without Web MIDI (notably Safari and Firefox have limited or no support)
- A device already held open exclusively by another application
- Audio — MIDI carries performance data, not sound
Troubleshooting
| Symptom | What to do |
|---|---|
| Unsupported browser | Use Chrome or Edge over HTTPS; Safari and Firefox currently have limited or no Web MIDI support. |
| No device shown | Reconnect the device and make sure no DAW or other app is holding it open, then reload. |
| Permission not granted | Allow MIDI access when prompted, or reset the permission in your browser’s site settings. |
| Notes but no sustain | Confirm your pedal sends CC64; some pedals need to be plugged in before powering the keyboard. |
FAQ
Which browsers support Web MIDI?
Chrome and Edge on desktop and Android. Safari and Firefox currently have limited or no support.
Why is no device shown?
Make sure it’s connected and not held open by another app (like a DAW), then reconnect.
Is my playing data sent anywhere?
No. MIDI messages are handled locally and never uploaded.
Do I need drivers?
Most class-compliant USB MIDI devices work without extra drivers; some interfaces provide their own.
Can I test both a keyboard and a controller?
Yes — all connected inputs are listed and their messages appear together in the log.
Does this make sound?
No. MIDI carries note and control data; you’d route it to a synth or DAW to hear it.