Keyboard testing guides.

Practical ways to understand what your keyboard is doing, and what to try next.

How to test every key

Open the keyboard tester, select the closest keyboard size and operating system, and press keys one at a time. The bright state means held; green means the key registered during this session. Test both Shift, Alt, and Control keys separately. Use the export button to save a local JSON report.

A key isn’t registering

1. Check that the page has focus and that your physical keyboard is connected.
2. Try the key in a plain text editor. If it works there, the browser or operating system may be intercepting it.
3. Reconnect the keyboard, try another USB port, or check the battery and wireless connection.
4. Review accessibility settings such as Filter Keys, Slow Keys, or Sticky Keys.
5. If the problem persists across applications and devices, consult the keyboard manufacturer’s support instructions.

A missing browser event alone does not prove a switch is broken.

Why Fn and certain shortcuts don’t appear

The browser receives keyboard events after the device firmware and operating system process them. Fn usually changes the keyboard’s internal behavior without sending its own event. System shortcuts, Print Screen, media keys, and some function keys can be intercepted. A website cannot reliably override these restrictions.

Repeated or sticky keys

Holding a key normally triggers operating system auto-repeat. Repeated events while holding a key are not evidence of switch chatter. If a quick tap produces multiple characters, compare the behavior in another application, check repeat and accessibility settings, and consult the manufacturer’s cleaning and repair guidance.

ANSI, ISO, and international keyboards

The visual tester currently represents US ANSI physical layouts in full-size, TKL and 60% sizes. Physical key positions use browser event codes, so different typed characters do not affect the same position’s highlight. ISO-only and other extra keys may appear in the last-key details and export without a matching visual keycap.

Testing on phones and tablets

This tool is designed for physical keyboards, including external keyboards connected to a tablet. A touchscreen software keyboard does not consistently generate the same key events. Scroll the keyboard horizontally on smaller screens.

Layout and browser references

The reference diagrams follow US ANSI conventions and the W3C keyboard event code standard, including its Apple extended keyboard example. Mac mode places Command beside the spacebar and Option outside Command. Apple’s keyboard shortcut reference explains modifier symbols and function-key behavior. For Windows shortcuts, see Microsoft’s keyboard guide.