Web MIDI API Standard and Controller Diagnostics
The W3C Web MIDI API allows web applications to communicate directly with Musical Instrument Digital Interface (MIDI) hardware over USB or Bluetooth MIDI.
Specialized Diagnostic
MIDI Controller & Keyboard Tester
Test USB MIDI keyboards, drum pads, pitch bend, and CC controllers online. Monitor MIDI note events, velocity (0-127), and control change messages free.
LAST MIDI NOTE --
NOTE VELOCITY (0-127) 0
CC MESSAGE / PITCH BEND 0
Live MIDI Event Stream
Click "Enable Web MIDI Access" above to begin monitoring real-time MIDI signals.
MIDI Signal Guidelines
Key velocity ranges from 1 (softest) to 127 (maximum dynamic velocity). Pitch bend and modulation wheel CC messages update continuously.
How to Get Started
Just three steps to run a complete controller test and understand your controller's health status.
01
Connect Controller
Connect your controller to your computer via USB cable or Bluetooth. If the browser doesn't respond, press any button on the controller to activate the connection.
02
Button Detection
Press each button in the visual interface and confirm the corresponding area lights up on screen. This helps troubleshoot unresponsive or double-clicking buttons.
03
Sticks & Vibration
Rotate the sticks to check linearity and drift issues; click the vibration test button to feel if the left and right motor feedback is working properly.
What would you like to do next?
Select a diagnostic calibration suite, deadzone analyzer, or high-frequency overclock tool.
Fix
Repair & Calibration
Calibrate zero-point offsets or follow step-by-step repair guides.
Optimize
Game Deadzones
Calculate exact radial vs axial deadzone overlays for Fortnite, Apex, & COD.
Telemetry
Overclock & Circularity
Verify true hardware polling Hz stability and statistical circularity grades.
Frequently Asked Questions
Everything you need to know about testing your controller.
How do I test a USB MIDI keyboard or drum pad online?
Connect your USB MIDI keyboard, synthesizer, or drum pad to your computer, click "Enable Web MIDI Access" above, grant browser MIDI permissions, and press keys or pads. Real-time MIDI note events and velocity levels will display.
What MIDI messages does this online tester monitor?
Our tool monitors MIDI Note ON/OFF, Note Velocity (0-127), Continuous Controller (CC) messages, Pitch Bend, and Modulation wheel parameters via the standard Web MIDI API.
Which browsers support Web MIDI API testing?
Google Chrome, Microsoft Edge, Opera, and Brave natively support the Web MIDI API on Windows, macOS, and Linux without installing external MIDI drivers.
How this test works & its limits
- This test reads your controller through the browser's standard Gamepad API — no drivers, no installs, nothing leaves your device.
- Readings depend on connection mode: Bluetooth reports at lower rates than USB. Compare like-for-like (wired vs wired).
- We measure the input reaching the browser — display lag and game-engine queues are outside this test's view.
- A clean reading now does not guarantee no drift in-game: deadzones differ per game, and wear develops over time. Use the Drift Timeline to track yours.
- This is a diagnostic, not a hardware-lab certification. For repair or RMA decisions, confirm with a second run or second tool.
100% Client-Side
All Gamepad API data stays in your browser. Zero tracking or data collection.
Instant Results
No downloads, plugins, or software installation needed. Works instantly.
Free Forever
No paywalls, subscription requirements, or hidden usage limits.