About KeyboardTester.io

KeyboardTester.io is a small, independent site with free tools for checking a keyboard in your browser and guides for fixing one that has stopped working. Nothing needs to be installed, and nothing you type leaves your device.

Who runs the site

I’m Harris Brown, a web developer from the United States. I’ve built websites for over 10 years, mostly with HTML, CSS and JavaScript. I write the guides on this site too; you’ll find them all on my author page.

The goal is a tester that checks the physical key rather than the letter it types, so it can tell a broken key from a keyboard set to the wrong language, works with any layout and doesn’t need an install.

What the tools do

  • Keyboard Tester: press every key and watch it light up. It covers full-size, TKL and 60% keyboards, Windows and Mac keys, and ANSI and ISO shapes. It also flags key chatter, when one press registers twice.
  • Keyboard Latency Test: measures the scheduling time between the browser’s key-event handler and its next animation-frame callback. It does not measure hardware latency.
  • Key Rollover Test: shows how many keys your keyboard can register at once, and whether some combinations block each other (ghosting).
  • Language keyboards: the tester labelled with the layout for your language, plus typing tools for Arabic and Farsi.

How the tester works

The tester listens for the physical key code your browser reports for each press (the KeyboardEvent.code value), not the character it types. That’s why it can tell you a key works even when Windows or macOS is set to the wrong layout. A few keys can’t be tested in any browser: Fn and some media keys are handled by the keyboard or operating system and never reach the web page.

Everything runs on your device. Your key presses aren’t recorded, saved or sent to a server. The privacy policy explains the cookies used for advertising, which pays for the site.

How the guides are written

Each guide starts from a real problem: a key that won’t respond, a laptop keyboard that locks, a layout that types the wrong characters. Guides are updated when Windows, macOS or iPadOS changes how things work, and every guide shows the date it was last updated.

If you find a mistake, or a fix that no longer works, please contact me with a link to the page. Corrections are made as soon as they’re checked.

Get in touch

Email [email protected] with bug reports, tool ideas or corrections, or follow @brownharrisdev on X.

Test every key on a keyboard in your language or layout. See all language keyboards.