Keyboard Tester

The main page is a full-size keyboard drawn on screen, from Escape and the function row down to the numpad. Press a key and it lights up. Counters show how many keys you've pressed, the last one and how many of the 104 remain, so on a quick pass you can see at a glance which key never registered. A history list keeps the recent presses, and a toggle swaps the labels between Windows and Mac layouts without changing what's being detected.

That makes it handy after a spill, when a new mechanical board arrives or before sending a laptop for repair. A whole column failing at once, for example, suggests a different problem from a single dead switch.

Two other tests cover faults the main map can miss. The ghosting test checks rollover, whether the keyboard registers several keys held at the same time, which matters in games where you might hold movement keys while pressing others. The double type test looks for chatter, where a worn switch sends two presses for one.

The page notes that some keys, such as system shortcuts, media keys and keys the operating system reserves, may never reach the browser, so a missing light on those doesn't always mean a faulty key. The layout is built for full-size keyboards, so compact boards will leave some keys untested. It's free with no signup, and the privacy policy says keystrokes are handled in your browser session and not stored as profiles, while feedback you choose to send goes to the site's own backend.