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Last key
A single dead key can drive you mad — a password that keeps failing, a shortcut that never fires, or a game character that refuses to jump. This tester makes the fault visible: press any key and its matching on-screen key lights up, so a key that stays dark is the one that is broken or sticking.
Everything runs locally in your browser, so your keystrokes are never recorded or transmitted. Use it after a spill, on a second-hand keyboard, or before a tournament to confirm every switch registers cleanly.
Some keys do not light up. Why? Modifier keys such as Fn and some media keys are often not reported by browsers. Letters, digits, punctuation and Space always are.
Does it work on mobile? It tests an external Bluetooth or USB keyboard. On-screen phone keyboards do not send the same events.
Why does my key repeat in the history? Holding a key triggers auto-repeat. A key that repeats without being held suggests a mechanical problem.
Test every key on your keyboard and spot broken or sticking switches. Press keys and watch them light up on a virtual keyboard, with a live readout of your last key and key code. Runs locally in your browser, so nothing you type is ever recorded.