Keyboard Tester
Press any key and it lights up on the on-screen keyboard. Keys you've pressed stay highlighted so you can spot dead or stuck keys, and holding several at once reveals ghosting and N-key rollover limits. Keystrokes never leave your browser.
Bright = currently held · Amber = pressed at least once. Some browser and OS shortcuts (like Win/Cmd combos) may be intercepted before they reach this page.
How to use the keyboard tester
Click anywhere on this page so it has focus, then start pressing keys. Each key you press turns bright while it's held and stays amber after you release it, building up a picture of every key that registered. To check a suspicious key, press it and watch for the highlight — if a physical key press produces no reaction on screen, that key (or its switch) is likely dead. The last key panel shows the character, the physical event.code, and the legacy keyCode, which is handy for debugging remaps and unusual layouts.
To hunt for a stuck key, press Reset highlights and then don't touch the keyboard: if any key lights up on its own, or a key stays lit after you let go, that switch is sticking. To test ghosting and N-key rollover, hold several keys down at once and watch the held now counter — on a basic membrane keyboard some combinations simply won't register beyond two or three simultaneous keys, while a good gaming keyboard will happily show six or more. That behaviour is explained in depth in our article below.
This tool reads standard keyboard events locally and stores nothing. A handful of combinations reserved by your operating system or browser (for example the Windows or Command key, or function-key media controls) may never reach the page, so their absence here isn't necessarily a fault.
Curious why some key combos don't work? Read keyboard ghosting and N-key rollover explained, or run the mouse test next.