MIDI Test: Check Your Keyboard and Controllers
See the notes, velocity, pitch bend and controls your MIDI keyboard or controller sends, and send a test note to a synth. Runs in Chrome, Edge and Firefox.
Runs in your browser. Your notes and MIDI messages never leave this device. No upload, no sign-up.
Plug in your keyboard or controller, then press Connect. Your browser asks for permission first.
Inputs
- Not connected yet
Outputs
- Not connected yet
Keys held: none
Send a test note
The test note is middle C (C4) at velocity 100, held for one beat at 120 BPM (half a second). It plays on whatever makes the sound: a synth, a sound module or your keyboard's own sounds.
| Time (s) | Port | Ch | Message | Data |
|---|---|---|---|---|
| Messages appear here, newest first. | ||||
Your report
Run the test above. Your results will appear here as plain text you can paste into a support chat, a return request or a forum post.
How to test a MIDI keyboard or controller
- Connect your keyboard or controller with a USB cable, or through a MIDI interface, and switch it on.
- Press Connect MIDI devices and allow access when your browser asks. Firefox asks you to add a site permission add-on first.
- Play some keys and move the wheels, knobs, sliders and pedals. Each key lights up on the screen keyboard with its velocity, and every message appears in the log.
- To test an output such as a synth or a sound module, choose it under Send a test note and press Send test note. You should hear middle C for half a second.
- Copy the report to keep a record, or to send to the maker's support team.
Which browsers can use MIDI devices
Web pages reach MIDI devices through Web MIDI. Chrome and Edge on a computer support it and ask your permission first. Firefox supports it from version 108, once you allow a site permission add-on for this site, which Firefox offers when you press Connect. Safari doesn't support Web MIDI on the Mac, iPhone or iPad. This page checks whether your browser offers Web MIDI rather than going by its name, and tells you if it doesn't.
Reading the message log
- Note on and note off carry the note number (60 is middle C, C4) and the velocity, from 1 to 127. Many keyboards end a note with a note on at velocity 0; the log shows that as a note off too.
- Control change (CC) messages carry a controller number and a value from 0 to 127. Standard numbers have names, such as 1 for the modulation wheel, 7 for volume and 64 for the sustain pedal. Many controllers send their knobs and pads on numbers without a standard meaning.
- Pitch bend has a finer range, from -8,192 to +8,191, and rests at 0.
- Aftertouch is pressure on a key that is already down: channel pressure is one value for the whole keyboard, key pressure one per key. Many keyboards don't send either.
- Program change switches sounds. The log shows programs as 1 to 128, as most instruments do, with the value sent (0 to 127) beside it.
Every channel message also carries a channel from 1 to 16, and the Data column shows the raw bytes in hexadecimal, which helps when you compare notes with a manual or a support team.
Faults this test can find
- Dead or doubled keys. Play every key from bottom to top. A key that never lights up sends nothing; one that sends two notes shows two note-on lines for one press.
- Uneven velocity. Play each key at the same strength. A key that always reads 127, or much lower than its neighbors, often has a dirty or worn contact.
- A sustain pedal that works backwards. Sustain pedal should read On only while you press it.
- Wheels and knobs. The pitch bend wheel should spring back to 0, and a knob should move smoothly through 0 to 127 without jumping or flickering when you let go.
- Outputs. Send test note checks the other direction: from your computer to a synth or sound module.
MIDI device not working? Try these fixes
No MIDI devices are listed
Your system may not see the device yet, another app may be holding it, or the cable may only carry power.
- Switch the device on and plug it straight into the computer, not through a hub. Try another USB port and another cable: a charge-only cable carries no data.
- New devices appear here by themselves once your system sees them; you don't need to reload.
Windows 11
- Right-click Start, open Device Manager and look for your device under Sound, video and game controllers. If it shows a warning sign, install the maker's driver.
- Close music apps such as Ableton Live, FL Studio or Cubase, then reload this page. On Windows a MIDI device can often be used by only one app at a time.
macOS
- Open Audio MIDI Setup (in Applications → Utilities) and choose Window → Show MIDI Studio. Your device should be there and not dimmed.
- If it is missing there too, the problem is the cable, the port or the device, not the browser.
The browser didn't ask, or access is blocked
Once you block MIDI for a site, the browser stops asking.
- In Chrome and Edge, click the icon at the left end of the address bar, allow MIDI devices, then reload the page.
- In Firefox, accept the prompt to add the site permission add-on. If you declined it, reload the page and press Connect MIDI devices again.
Some work and school computers turn MIDI off for every website. Ask your IT team, or test on another computer.
The device is listed, but nothing appears when you play
The keyboard may send on another port, or its settings may stop it sending over USB.
- Some devices have several ports. Play and watch which input's message count goes up.
- Check the keyboard's MIDI or USB settings: options such as MIDI out or the USB MIDI mode can turn sending off.
- With a 5-pin MIDI cable, connect the keyboard's MIDI OUT to the interface's MIDI IN, not IN to IN.
The test note makes no sound
An output only carries the note; a synth, a sound module or the keyboard's own sounds have to play it.
- Check that the receiving device listens on the channel you chose. Channel 1 is the usual default.
- Turn up the synth's volume and check that its audio is connected to speakers or headphones.
- Press All notes off if a note keeps sounding.
Windows 11
- Microsoft GS Wavetable Synth, if it is listed, plays through your speakers: check the Windows volume.
The sustain pedal works backwards
Pedals come in two polarities. Plugged into a keyboard that expects the other kind, a pedal reads as pressed when you release it.
- Switch the keyboard off, plug the pedal in, then switch the keyboard on: many keyboards detect the pedal's polarity when they start.
- If the pedal has a polarity switch, flip it.
Common questions
Does this MIDI test work in Safari?
No. Safari doesn't support Web MIDI, on the Mac or on iPhone and iPad, so web pages can't see MIDI devices there. Use Chrome or Edge on a computer, or Firefox 108 or later, which asks you to allow a site permission add-on first.
Why does my browser ask for permission to use MIDI devices?
Browsers treat MIDI devices like other hardware and ask before a page can use them. This page asks only for ordinary MIDI messages, not system exclusive (SysEx) messages, which editor apps use to back up and change a device's settings. It sends nothing to your devices unless you press Send test note or All notes off.
Why is middle C shown as C4 when my keyboard calls it C3?
Makers number octaves differently. This page calls MIDI note 60 C4, the most common convention, but some makers call the same note C3. The note number in brackets, 60, is the same everywhere.
What is MIDI velocity?
Velocity is how hard, strictly how fast, you pressed a key, sent as a number from 1 to 127 with each note. A key that always sends 127, or much less than its neighbors, can point to a dirty or worn key contact. Most keyboards also let you choose a velocity curve in their settings.
Why do I see clock or active sensing messages?
Some devices send timing messages all the time: MIDI clock, 24 per quarter note, keeps other gear in tempo, and active sensing, a few times a second, says the device is still connected. The log hides both unless you turn them on, but it counts them and shows the clock's tempo.
Can I test a Bluetooth MIDI keyboard?
Yes, once your computer has connected it as a MIDI device. On a Mac, connect it in Audio MIDI Setup, in the MIDI Studio window's Bluetooth settings; it then appears here like a USB device. Browsers on Windows may not list Bluetooth MIDI devices, so if yours doesn't appear, test it with a USB cable.
Do I need a driver for my USB MIDI keyboard?
Usually not. Most USB keyboards and controllers are class compliant: they work without a driver and appear as soon as you plug them in. Some older or larger instruments need the maker's driver, especially on Windows, so check the maker's support page if yours doesn't appear.
Something not right?
Tell us if your device wasn't found or a result looks wrong. Your browser, system and device model help us check.
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