This is the central page for a collection of online MIDI VST resources.
Connect to a midi device in the browser
Connecting to MIDI in a browser (using the Web MIDI API) can be tricky because it involves both hardware permissions and specific browser security requirements.
Here are the most common reasons why your application might fail to detect or connect to MIDI devices:
1. Missing User Permissions
MIDI access often requires explicit user permission. When an application requests midi access, the browser should prompt the user.
If the user previously blocked this request, the application won't see any devices.
- Check the site settings in your browser (usually by clicking the lock icon next to the URL) and ensure "MIDI devices" permission is set to "Allow."
2. Browser Support
Not all browsers support the Web MIDI API.
- Chrome, Edge, and Opera: Excellent support.
- Firefox: Supported, but sometimes requires a plugin or specific configuration (dom.webmidi.enabled in about:config). Firefox installed with snap on linux doesn't seem to work atm.
- Safari:Midi API not supported in Safari atm
Take a look at caniuse.com midi support for the latest information.
3. Hardware Exclusive Access
On some operating systems (especially Windows), a MIDI device can only be opened by one application at a time.
- If you have a DAW (like Ableton, FL Studio, or Logic) or another browser tab open that is using the MIDI device, close them and refresh your browser.
4. Physical Connection Issues
Sometimes the simplest things are the cause.
- Ensure the MIDI controller is powered on before the browser is launched.
- Try a different USB cable or port.
- Use a tool like Web MIDI Console to see if the browser sees the device independently of your code.
Debugging Tip:
Open your browser's Developer Console (F12). If the Web MIDI API is failing for security reasons,
you will often see a specific error message like DOMException: Permission denied or Midi access is not supported in this context.
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