MIDI keyboard test

After you allow MIDI access you get a live view of everything your controller sends:

• Inputs: each connected MIDI input with its name, manufacturer, state and port status. The list updates automatically when you plug a device in or out.
• Keys: pressed keys light up on an on-screen keyboard, shaded by how hard you hit them.
• Velocity: the last note's velocity (1–127) with a meter, plus the highest velocity so far.
• Counters: total key presses, how many different keys you've pressed, and how many are held right now.
• Controls: sustain pedal up or down, mod wheel position and pitch bend value.
• Message log: the last 200 messages, decoded into plain English with the channel number and the raw bytes in hex.

Choose the keyboard size that matches your instrument: 25, 37, 49, 61, 76 or 88 keys. Then play every key from bottom to top. The different keys counter should reach the number of keys on your keyboard. If a key never lights up, or a note shows up that you didn't press, that key or its contact strip may need cleaning or repair.

To check velocity, play one key softly, then hard. A healthy keyboard sends a wide range, typically from below 20 to over 110. If every press reads about the same, check the velocity curve setting on the keyboard itself. Notes pressed outside the visible range are listed below the keyboard so nothing gets missed.

Each line shows the time, the MIDI channel, the message type and its details:

Message	What it means
Note On / Note Off	A key was pressed or released, with the note name and velocity
Control Change (CC)	A knob, slider, wheel or pedal moved. CC 1 is the mod wheel, CC 64 the sustain pedal, CC 7 volume
Pitch Bend	The pitch wheel moved; 0 is the center
Program Change	A preset or sound was selected
Aftertouch	Pressure applied after the key was pressed
Timing Clock	Tempo sync, 24 per quarter note

Timing Clock and Active Sensing messages can flood the log, so they're hidden by default; uncheck the option to see them. When a clock is received, the test also estimates its tempo in BPM. Pause freezes the log, Clear resets everything, and Sound lets you hear the notes.

The test uses the Web MIDI API, which works in desktop Chrome, Edge, Opera and Firefox, and in Chrome on Android. Safari and every browser on iPhone and iPad don't support Web MIDI.

If nothing shows up:

• Make sure the page is opened over https and you allowed MIDI access (check the icon next to the address bar).
• Close other programs that use the keyboard, such as a DAW; on Windows, some drivers allow only one app at a time.
• Try another USB cable or port, and avoid unpowered hubs.
• Bluetooth MIDI devices must be paired in your operating system first.

Everything runs in your browser; no MIDI data is sent anywhere. To actually play music with your controller, try the online piano.