Connect the Device
Plug your MIDI keyboard into your computer using USB, or pair supported Bluetooth MIDI hardware in your operating system.
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MIDI Tester Online Free
Test your MIDI keyboard, drum pads, pedals, knobs and controllers directly in your browser. See every played note, velocity, control change and MIDI event as it happens.
STEP 01 · DEVICE CONNECTION
Checking browserConnect Your MIDI Keyboard
USB MIDI and Bluetooth MIDI devices work when your operating system makes them available to a supported browser.
Ready to detect MIDI devices
The page checks for a MIDI connection automatically when your browser allows it. If a permission request appears, choose Allow.
0Inputs
0Outputs
Not connectedAccess status
Use HTTPS and a Web MIDI compatible browser. No SysEx access is requested.
STEP 02 · INTERACTIVE LIVE INPUT
88-Key MIDI Keyboard Tester
Play any note from A0 (MIDI 21) to C8 (MIDI 108). Active keys glow purple; keys received during this session retain a soft mark. Notes outside the piano range still appear in the event log.
A0 · MIDI 21Scroll horizontally to see all 88 keysC8 · MIDI 108
Latest Note—MIDI note —
Velocity—
Held Notes0Active Note On events
Keys Seen0 / 88In the piano range
DETAILED PERFORMANCE READINGS
Live MIDI Activity and Controls
Read actual MIDI data for notes, controllers and transport messages. Missing values mean your device has not sent that message yet.
Messages Received0Hardware input messages
Note On0Real note presses
Control Changes0Knobs, faders and pedals
Active Channel—Latest incoming message
Pitch Bend
—−81920 · Centre+8191
14-bit value, relative to centre. Wheel data appears only if your controller sends pitch-bend messages.
Modulation Wheel · CC 1
—0127
Mod wheel, ribbon or a mapped controller depending on your hardware.
Sustain Pedal · CC 64
Not received—CC value
Values 64–127 normally mean pedal down. Values 0–63 mean pedal up.
Aftertouch & Program
Channel Pressure—
Program Change—
Last CC—
MIDI Clock BPM—
Tempo is estimated from received MIDI Clock pulses, if sent by a sequencer.
Velocity Response History
Compare soft and hard playing. The 24 latest real Note On velocities are displayed.
Play a few notes to display your velocity history.
Soft · 1Hard · 127
REAL-TIME MIDI MONITOR
MIDI Event Log and Message Decoder
Inspect the exact event type, MIDI channel, source and hexadecimal data received by the browser. Use filters to focus on notes, controllers or system messages.
| Time | Source | Channel | Event | Details | Hex Bytes |
|---|---|---|---|---|---|
| Connect a MIDI device and play notes to see live events. | |||||
0 visible · Max 500 recent events in session
OPTIONAL · MIDI OUTPUT CHECK
Test a MIDI Output Port
Select an output device above, then send a short Middle C message to a synthesiser or MIDI interface. Output tests are optional and never start automatically. Turn down connected speakers first.
No MIDI output selected.
QUICK START GUIDE
How to Test a MIDI Keyboard Online
Follow these five steps to verify that your keyboard or controller sends messages correctly before configuring your music software.
Allow MIDI Access
Open the tool in HTTPS. Choose Allow when the browser requests MIDI permission, or press Connect MIDI Devices.
Play Every Key
Press keys across the keyboard. Look for matching purple piano highlights, note names and velocity values.
Try Pedals and Knobs
Move the mod wheel, pitch bend, sustain pedal, pads, encoders and faders. Watch their real message values.
Review Your Log
Filter the message list, compare events and export the results in CSV or JSON when troubleshooting.
ILLUSTRATED GUIDE 01
Connect a MIDI Keyboard to Your Computer
A MIDI keyboard does not have to include speakers to work with this tester. It only needs to send MIDI messages through a compatible USB connection, interface or Bluetooth MIDI connection.
For USB controllers, connect the cable, power the keyboard on and verify that your operating system detects it. For traditional 5-pin MIDI equipment, connect it through a compatible USB-MIDI interface.
Once the device appears in the input selector above, play a note and confirm that the event log updates.
IMAGE SECTION 01MIDI Keyboard Connection DiagramAdd your image URL to data-image-url on this figure
MIDI MESSAGE REFERENCE
Understanding MIDI Notes, Velocity and Controllers
Each incoming MIDI event is a short digital message, not recorded audio. These are the most useful event types to examine when diagnosing a MIDI device.
Note On and Note Off
Note On starts a key press and usually carries a velocity from 1 to 127. Note Off releases the note. A Note On with velocity 0 is treated as Note Off.
Velocity Sensitivity
Velocity describes how the instrument reports a note strike. Compare gentle presses and firmer presses. A constant value may reflect a fixed-velocity setting, not necessarily a damaged sensor.
Control Change (CC)
Controller messages carry a CC number and a value from 0 to 127. CC 1 is commonly modulation, CC 7 volume, CC 11 expression and CC 64 sustain.
Pitch Bend
Pitch bend uses 14-bit data. The centre is 8192, shown here as zero, with relative values from −8192 to +8191.
Aftertouch
Channel pressure and polyphonic key pressure communicate pressure after a note begins. Only keyboards supporting these features send them.
Clock and Transport
Sequencers can send timing messages, Start, Stop and Continue events. Standard MIDI Clock uses 24 pulses per quarter note.
ILLUSTRATED GUIDE 02
Check Keys, Pads, Pedals and MIDI Wheels
A keyboard test should include more than playing a scale. For a thorough check, trigger each pad, rotate the encoders, move the pitch and modulation wheels, and press the sustain pedal.
Watch the event details to confirm that the correct control number is transmitted. For example, moving a sustain pedal typically produces CC 64 events, while pitch bend produces a different MIDI message family.
If a key or knob never appears, compare with your device's MIDI mapping settings and repeat the test using another cable or application.
IMAGE SECTION 02MIDI Controls and Message TypesAdd your image URL to data-image-url on this figure
PRACTICAL TROUBLESHOOTING
Why Is My MIDI Keyboard Not Working?
Use the results above to narrow down whether the issue is browser permission, a missing input port, a MIDI mapping setting or your controller.
Browser Cannot Access MIDI
Check that the page is loaded over HTTPS. Use a compatible browser such as Chrome, Edge, Opera or supported desktop Firefox. Safari and iOS browsers generally do not offer Web MIDI.
Keyboard Does Not Appear
Verify that the cable carries data, power the device on, check its USB-MIDI mode and reconnect it. Some controllers require a vendor driver or operating-system setup.
No Notes in the Event Log
Choose All connected inputs and All 16 channels. Then play several keys. If controller messages appear but notes do not, inspect the device's mapping or active mode.
Stuck or Missing Keys
A Note On without a matching Note Off can suggest a lost message or configuration issue. Repeat the test and compare results in your DAW before concluding that hardware is defective.
Velocity Appears Constant
Check whether fixed-velocity mode or a velocity curve is enabled. Test soft and firm presses. This tool displays received values but cannot diagnose the key sensor internally.
Bluetooth MIDI Not Detected
Pair the device using the operating system's MIDI-capable connection workflow. Ordinary Bluetooth pairing alone may not expose a MIDI port to the browser.
COMPATIBILITY & PRIVACY
Where Does the MIDI Tester Work?
Web MIDI availability depends on the browser, operating system, hardware and website permission policy. Chrome, Edge and Opera are common choices, with support also available in current desktop Firefox. Safari and standard iOS browsers do not provide native Web MIDI support.
This tester uses the browser's Web MIDI API to process event data locally. It does not upload MIDI notes, device information or log exports. Other parts of the website may have their own analytics and privacy policies.
View current browser compatibility before troubleshooting unsupported devices.
HTTPSSecure connection requiredNo installation · No SysEx permission
HELP & ANSWERS
MIDI Tester Frequently Asked Questions
Can I test my MIDI keyboard online for free?
Yes. Connect your keyboard, grant permission in a compatible browser and play notes. The live MIDI monitor does not require a subscription.
Does the MIDI tester connect automatically?
It attempts to obtain MIDI access when the page loads. Browsers may require permission or a button click, so a Connect MIDI Devices button is also provided. Device listings update when connected MIDI ports change.
Does this work with USB MIDI and Bluetooth MIDI?
Both can work if the operating system exposes the hardware as a MIDI input to the browser. The connection method alone does not guarantee that the device will appear.
Can I test an 88-key digital piano or a 25-key controller?
Yes. The onscreen piano covers standard 88-key note numbers, and the event log reads note data even when your device has fewer keys. Notes outside the displayed 88-key range are still logged.
Will the MIDI tester produce sound?
MIDI messages are instructions rather than audio. Enable optional tone preview to hear a basic synthesized tone when you press keys. This does not test your keyboard's built-in audio output or sound quality.
How do I test sustain and modulation?
Press the sustain pedal and look for CC 64 messages. Move the modulation wheel and look for CC 1. Manufacturers can remap controls, so consult your device's configuration.
Can this tool detect faulty keys?
It shows which notes arrive and their velocities. Missing messages can indicate a mapping, cable, driver or hardware issue, but a browser test alone cannot conclusively identify a faulty key.
What is the difference between MIDI and audio recording?
MIDI describes note and controller events, whereas audio recording captures sound waves. The CSV and JSON downloads contain MIDI event data, not an audio recording or a playable MIDI music file.
Does the tester measure MIDI latency?
No. Event timestamps can help order messages, but they do not independently measure physical key-to-computer latency or audio round-trip delay.
Does it support MIDI SysEx messages?
This tester deliberately requests MIDI access without SysEx permission. Device-specific SysEx transfers are outside the scope of this tool.
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