DeviTestKeyboard test
Press every key. Each one turns green when it works, so dead keys stand out immediately.
How to use it
- Click once on this page so it receives your key presses.
- Press every key one by one. Keys turn blue while held and green once tested.
- Watch the "Last key" line: it shows exactly what the browser received.
What the results mean
- A key never turns green: it isn't sending a signal. Clean under it, try another USB port or reconnect Bluetooth.
- A key stays blue after you let go: it may be sticky or stuck down.
- The wrong key lights up: your system keyboard layout may be different from the physical one.
Some keys can't be tested in a browser because the system grabs them first, such as Fn, the Windows key on some systems, Print Screen and media keys. The layout shown is a standard US layout; other layouts still work because the test uses each key's position.
Testing several keys at once (N-key rollover)
Hold down keys one after another — for example A, S, D, F, J, K, L — and watch "Most keys held at once". Gaming keyboards often register 6 keys or more; many office and laptop keyboards stop at 2–6, or only for some key combinations ("ghosting"). The number you see is what reached the browser: the operating system, the USB mode of the keyboard and the browser can all lower it, so it is not a guaranteed maximum for the hardware.
ANSI, ISO and other layouts
The drawing uses a US (ANSI) layout with the extra ISO key next to the left Shift, shown with a dashed border. The test identifies keys by their physical position, so an Arabic, German or French layout works too — only the labels differ. Keys with a dashed border, the editing block and the number pad are optional: laptops and compact keyboards often don't have them.
Key chatter and stuck keys
If a key sends a second press within 30 ms of being released, the test warns about possible chatter — a worn or dirty switch that types double letters. If a key stays "held" for several seconds while you're not touching it, the key may be stuck or its release signal may be getting lost.