Keyboard Tester

Every time you press a key, your keyboard sends an event to the browser. This tester listens for those events and lights up the matching key on the on-screen layout — blue while the key is held down, green once it has registered at least once.

The tester reports two values for each press: event.key is the character or action the key produces (like "a" or "Enter"), while event.code identifies the physical key position (like "KeyA"), independent of your language layout. Comparing the two is useful when diagnosing layout or language issues.

A working key should light up instantly on every press. If a key never lights up, the switch or membrane contact underneath it is likely faulty. If a single press registers multiple times in the history, the switch is "chattering" — a common sign of wear on mechanical keyboards.

Keys pressed together should all show as held at the same time. If some combinations fail to register, you are hitting the keyboard's rollover limit (often 6 keys over USB), which is normal on many keyboards rather than a defect.

Some shortcuts are reserved by the operating system or browser — for example the Windows key menu or Ctrl+W — and cannot be fully captured by any web page.