Online Keyboard Tester

What is this tool?

A dedicated, distraction-free page for working through a whole keyboard. It carries the same event engine as the home-page tester but adds more form factors and a running key history.

Five sizes are selectable — Full (104), TKL (87), 75%, 65% and 60% — plus a Windows or Mac modifier row, so the diagram matches compact and Apple boards instead of approximating them.

The page also explains the concepts behind what you are seeing: what a keyboard tester is, N-key rollover, chatter and switch bounce, keyboard sizes and form factors, and how to verify a suspicious key.

How to use it

1. Choose your form factorFull (104), TKL (87), 75%, 65% or 60%. Picking the right one matters most on compact boards, where one physical key carries two or three legends.
2. Set Windows or MacThis swaps the modifier row so Alt/Option and Ctrl/Command sit where they do on your machine.
3. Press each key and watch the historyEvery press is appended to the key history list, so you can confirm a key registered even if you were looking at a different part of the screen.
4. Use Clear History between passesClear History empties the log without resetting the diagram, which keeps a second pass readable.

What the results mean

Highlighted keys

A key highlights on keydown and returns to its tested colour on keyup. A key that highlights and stays highlighted after you release it means no keyup arrived — worth a second look.

Key history

A chronological list of what the browser reported. It is the fastest way to catch a key that fires twice from one press, because you will see the same entry back to back.

N-key rollover in practice

The page explains the difference between 2KRO, 6KRO and NKRO. To find out which one your keyboard behaves like, use the Anti-Ghosting Test — that tool is built to hold combinations and count what survives.

What it can detect

• Dead keys, on any of the five documented form factors
• Keys that report the wrong code, visible as a mismatch between what you pressed and what lit up
• Double firing from a single press, visible as a repeated entry in key history
• Modifier keys that latch on and stay active

Limits worth knowing

A browser can only report what the platform gives it. These are the honest boundaries of this page, so a result is never read as more than it is.

• The tester reads browser key events. It cannot see switch travel, actuation force or the keyboard's internal scan rate.
• Rollover behaviour shown here is what survived the whole chain — keyboard, cable, operating system and browser. It is not read from the keyboard's firmware.

Tips

• On a 65% or 60% board, test the layers too — hold the Fn key and confirm the arrow cluster or function row still produces events.
• If your keyboard has firmware layers, switch to the base layer first so what you press matches what you expect.
• Chatter is easier to prove with the Double-Click Test, which times the gap between the two events.

Troubleshooting

Related documentation

• KeyboardOnline Keyboard TestThe keyboard tester on the home page — press keys, watch them light up.
• KeyboardBroken Key DetectorA guided pass over every physical key, plus a consistency re-test for the ones that look wrong.
• KeyboardStuck Key DetectorWatches for keys that go down and never come back up, with an adjustable hold threshold.
• KeyboardAnti-Ghosting TestChecks whether simultaneous key presses all arrive, and how many your board can hold at once.
• KeyboardHID Keyboard TesterBrowser key events side by side with raw WebHID reports, when your browser supports it.