Keyboard Tester
Press any key and watch it light up on the on-screen keyboard below. Free, instant and private — every keystroke is read locally in your browser and nothing is ever sent anywhere. Great for spotting stuck, dead or ghosting keys.
Keys highlight while held and stay marked once tested. Browser and system shortcuts (Ctrl/⌘ combos, Alt+Tab, F11, F12) are handled by your operating system and may not be captured here.
How to use the keyboard tester
- Click the page once. This gives the tester keyboard focus so it can read your keystrokes. If keys do not respond, click anywhere on the page and try again.
- Press each key. Every key you press lights up on the on-screen keyboard and its name, physical code and keyCode appear at the top. Tested keys stay tinted so you can see what is left.
- Check for problems. Work across the whole keyboard. Any key that never lights up is likely dead or disconnected; a key that stays lit after you release it may be stuck.
About this tool
This keyboard tester helps you diagnose a laptop or external keyboard without installing any software. It reads the browser's keydown and keyup events and maps each physical key by its event.code, so it works the same whether your layout is QWERTY, AZERTY or Dvorak — the position that lights up matches the key you actually pressed. The live readout also shows event.key (the character produced) and the legacy keyCode, which is handy for web developers wiring up keyboard shortcuts.
Everything runs locally in your browser; your keystrokes are never recorded, uploaded or logged, so it is safe to type freely while you test. Use it to check a keyboard before buying it second-hand, to confirm a spilled-drink repair worked, or to find the exact key codes you need when building a game or an app. Note that a few keys — the Fn key, some media buttons, and OS-reserved combinations — are intercepted by hardware or the operating system before the browser sees them, so they may not register.
Frequently asked questions
Why do some keys not light up?
A key that never responds is usually physically dead, disconnected or blocked at the operating-system level. The Fn key, certain media and brightness keys, and reserved combinations such as Alt+Tab or Ctrl+Alt+Delete are captured by your hardware or OS before the browser receives them, so those may not register even on a healthy keyboard.
What is the difference between "code", "key" and "keyCode"?
event.code is the physical key's location and never changes with your layout (for example KeyA is always the key where A sits on US QWERTY). event.key is the character actually produced, which depends on layout and modifiers (a, A, or an accented letter). keyCode is an older numeric identifier kept for backward compatibility.
How do I test for key ghosting or a stuck key?
To check ghosting, hold several keys down at once and watch how many light up together — cheaper keyboards drop simultaneous presses. To find a stuck key, release everything: any key that stays highlighted after you let go is registering as continuously pressed.
Is anything I type recorded or sent to a server?
No. The tester processes key events entirely in your browser with JavaScript and keeps no history. Nothing you press is stored, uploaded or logged, so it is completely private.