Online MIDI Controller Tester
Plug in any USB MIDI controller and see notes, velocity and channels live in your browser. No install, no driver, no signup. When it works — make a beat with it.
Web MIDI is not supported in this browser.
Web MIDI works in Chrome, Edge, Opera, Brave and recent Firefox on desktop, plus Chrome on Android. Safari does not implement Web MIDI on macOS or iOS — try one of the supported browsers.
Controller working? Make a beat with it.
Padwolf is a free 16-pad beat maker that runs in the same browser tab. You'll Allow MIDI once more on the beat maker — same click, then play.
Open the beat makerMIDI not working? Step-by-step fix
The most common issue is that the permission prompt never appears. Work through these in order — about 90 % of cases are solved by the first four checks.
1. Before touching browser settings
Click "Connect MIDI" first
Browsers don't ask for MIDI permission on page load. The prompt only appears after you click the button. If you haven't clicked it yet, scroll up and do that — the prompt should appear within a second.
Watch for the prompt at the top of the window
The MIDI permission prompt appears as a small dialog under the address bar (Chrome, Edge, Brave, Opera) or as a panel that slides down from the address bar (Firefox). It's easy to miss if you're focused on the page.
Plug the controller in via USB before clicking
If no device is plugged in, the prompt may not appear at all in some browsers, or you'll see "Permission granted" with zero devices. Plug in first, then click.
Try a different USB cable or port
Some USB-C cables are charge-only and don't carry data. Try a known-good cable. On desktops, try a back-panel USB port — front-panel ports are sometimes flaky.
2. Reset MIDI permission in your browser
Pick your browser:
- Click the lock icon to the left of the URL
- Click "Site settings"
- Find "MIDI devices" in the permissions list — set to "Allow"
- Reload the page (the prompt will reappear when you click Connect MIDI)
- Click the lock icon to the left of the URL
- Click "Permissions for this site"
- Set "MIDI device control" to "Allow"
- Reload the page
Note: If you're on a managed/enterprise Edge install, your IT policy may block MIDI globally — check edge://policy.
- Click the Brave Shield (lion icon) and confirm Shields are down for padwolf.app, OR keep them up — Shields don't block MIDI but advanced fingerprinting protection can interfere
- Click the lock icon → Site settings → set MIDI devices to Allow
- Reload the page
Note: Brave behaves like Chrome for Web MIDI in 99% of cases. If the prompt never appears, disabling "Strict" fingerprinting in Brave Shields usually fixes it.
- Click the lock icon
- Click "Site settings"
- Set MIDI devices to Allow
- Reload the page
- Confirm you're on Firefox 108 or newer (about:support shows version) — older versions have no Web MIDI
- Click the lock icon to the left of the URL → Connection secure → More information
- In the Page Info window, click the Permissions tab
- Find "Use MIDI devices with SysEx support" — uncheck "Use Default" and set to Allow
- Reload the page
Note: Firefox is stricter about MIDI than Chromium browsers. If the prompt is silently denied, check about:config for `dom.webmidi.enabled` (should be true) and `dom.webmidi.gated` (default true is fine).
- Switch to Chrome, Edge, Brave, Opera, or Firefox 108+
- On iPhone / iPad, install Chrome or Edge from the App Store — note that even those use Safari's WebKit underneath, so MIDI is unavailable on iOS regardless of which browser app you use
- Use a Mac, Windows, Linux, ChromeOS, or Android device with a Chromium-based browser
Note: There is no workaround inside Safari. Apple has not implemented the Web MIDI API in WebKit, and on iOS all browsers are required to use WebKit, so iOS Chrome / Edge / Firefox can't help either.
3. Confirm your operating system sees the controller
If the OS doesn't see the controller, no browser will. Pick your OS:
Open Audio MIDI Setup (Applications → Utilities) → Window → Show MIDI Studio. Your controller should appear with a colored icon. If it's greyed out, macOS isn't seeing it — try a different cable / port and reboot.
Open Device Manager → "Sound, video and game controllers". Your controller should be listed. If you see a yellow warning triangle, right-click → Update driver. Most class-compliant MIDI controllers don't need a driver, but a few (older M-Audio, some Roland) do — grab it from the manufacturer's site.
Run `aconnect -l` in a terminal. Your controller should appear as a client with port(s). If not, run `lsusb` to confirm the kernel sees the USB device, then check `dmesg` for MIDI-related errors. ALSA usually handles class-compliant USB MIDI without setup.
Class-compliant USB MIDI controllers work out of the box. If yours doesn't appear, try a different USB-C cable — some Chromebooks are picky.
Frequently Asked Questions
Plug in your USB MIDI controller, click "Connect MIDI" above, and approve the browser permission prompt. Hit any key or pad — you should see note, velocity and channel update in real time. If nothing shows up, try a different USB cable or port.
Chrome, Edge, Opera, Brave and recent Firefox (108+) on desktop, and Chrome on Android. Safari does not support Web MIDI on either macOS or iOS — use Chrome on those platforms instead.
The browser asks before any page can read MIDI input. It's a one-time prompt per site. After you click "Allow" the controller stays connected for as long as the tab is open. Padwolf never sends that data anywhere — it's used to test the device and (if you continue) to play pads in the beat maker.
Sometimes. Bluetooth MIDI on Chrome/macOS is the most reliable; Windows requires extra setup. For testing we recommend a USB connection — it's plug-and-play across every supported browser.
Velocity is how hard you struck the pad or key, sent as a number from 1 to 127. Higher velocity normally maps to higher volume. The bar above shows the live velocity of your last note — useful to confirm a pad's velocity sensor is working.
Yes — that's the whole point. Once the tester confirms your controller works, click "Open beat maker" to drop into Padwolf with 16 pads ready to play. You'll be prompted for MIDI access once on the beat maker too — same Allow click, then your controller is live.