Keyboard Tester

See Exactly What Your Keyboard Sends

A keyboard tester is the fastest way to confirm a keyboard is fully working before you buy it secondhand, after you clean it, or when a game keeps missing your inputs. This tool draws a full on-screen QWERTY layout and lights up each key the instant you press it. The moment a key registers it turns green and stays green, so after a quick sweep across the board you can see — at a glance — which keys responded and which never lit up.

Because the tool maps the physical event.code rather than the printed character, it behaves identically whether you run QWERTY, AZERTY, or Dvorak, and it does not care whether Caps Lock or Shift is engaged. The live readout above the board always shows the most recent event.key (the character produced) next to its event.code (the physical position), which is handy when you are debugging remaps or a misbehaving key.

What This Test Actually Checks

This tester answers three practical questions about your hardware:

• Does every key work? Press them all. Anything still grey is a candidate dead switch.
• Do any keys stick? A switch that stays highlighted blue after you let go, or that keeps repeating in the readout, is sticking and needs cleaning or replacing.
• How good is your rollover? Hold many keys together and watch the Max Rollover counter climb.

How to Interpret Your Results

Aim for 100% coverage on a healthy board. Work methodically: number row, top letter row, home row, bottom row, then modifiers, space, function keys, and the arrow and navigation cluster. If a single key refuses to turn green, try pressing it a few more times and from different angles — intermittent registration often means dust or a tired switch rather than total failure.

For rollover, a result of 2-3 keys is typical of basic membrane keyboards and is fine for everyday typing. Gamers usually want 6-key rollover or full NKRO so that simultaneous movement, jumping, and actions never drop. If holding a specific trio of keys causes a fourth to stop responding, you have found a ghosting combination baked into the keyboard matrix — note it and test whether it affects keys you actually use together.

Troubleshooting Tips

• A key won't register at all. Power down, pop the keycap, and blow out debris with compressed air. Reseat the cap firmly. On laptops, a failed key may need a new switch or membrane.
• A key sticks or repeats. Sticky residue under the cap is the usual culprit. Clean around the switch; if it persists, the switch itself is worn.
• A whole row is dead. That points to a cable, ribbon, or controller fault rather than individual switches — common after a liquid spill.
• Nothing registers. Check the cable or wireless dongle, try another USB port, and confirm the OS sees the device.
• Some keys never fire here. PrintScreen and certain media or Fn keys are grabbed by the OS before the browser receives them; that is expected, not a fault.

Reaction speed matters as much as key health for gaming, so once your board passes, benchmark your reflexes with the reaction time test and measure your real-world input speed with the typing speed test. Use the Reset button anytime to clear the green state and run a fresh sweep.