A Virtual Keyboard Tester is an online tool that lets you test every key on your physical keyboard. It displays a visual keyboard on screen and highlights keys in real-time as you press them. It shows detailed information about each keystroke, including key name, key code, modifier states (Shift, Ctrl, Alt, Meta), and whether the key event is a repeat. This is useful for diagnosing faulty keys, testing new keyboards, checking key mappings, and understanding how your browser interprets keyboard input.

Simply start pressing keys on your physical keyboard. The corresponding keys on the virtual keyboard will light up in blue. Modifier keys (Shift, Ctrl, Alt, Win/Cmd) show a distinct orange highlight when active. The detail panel on the left displays full information about the most recent key press. The history panel tracks your last keystrokes. You can also click on the virtual keys with your mouse to simulate key presses — this is especially useful on touch-screen devices or when testing without a physical keyboard connected.

Several reasons can cause this: (1) The key may be physically broken or stuck — test on another device to confirm. (2) Some keys (like Print Screen, Pause/Break, or media keys) may not trigger standard JavaScript keyboard events due to browser or OS interception. (3) Certain browser shortcuts (e.g., Ctrl+T, F5) may be captured by the browser before reaching this tool. (4) If you're on a laptop, the Fn key often doesn't send a standard key event. (5) Check if your keyboard layout matches the US QWERTY layout displayed — keys like the Windows/Mac Command key may map differently on non-US layouts.

key returns the character produced by the key press (e.g., "a", "A", "!", "Enter"). It respects the Shift key and keyboard layout. code returns the physical key location on the keyboard (e.g., "KeyA", "Digit1", "ShiftLeft") — it's layout-independent and stays the same regardless of modifiers. keyCode and which are legacy numeric codes (e.g., 65 for 'A') — they are deprecated but still widely supported. For modern development, prefer event.key and event.code. This tool displays all four values so you can compare them in real time.

Yes! This tool tracks all modifier key states in real time. When you press and hold a modifier (like Ctrl, Shift, Alt, or Win/Cmd), its indicator at the top lights up and the corresponding virtual key stays highlighted. While holding the modifier, press another key and you'll see the combination registered in the detail panel (e.g., ctrlKey: true). The history chips also show the full combination context. Note that some system-level shortcuts (like Alt+Tab or Ctrl+Alt+Del) are intercepted by the operating system and won't reach the browser.

N-key rollover (NKRO) is the ability of a keyboard to register multiple simultaneous key presses correctly. A keyboard with full NKRO can register every key pressed at once without any missed strokes. Cheaper keyboards may have 2KRO or 6KRO (only 2 or 6 keys at a time). Ghosting occurs when a keyboard registers a key you didn't press because of matrix limitations. Use this tester to press multiple keys simultaneously — if all pressed keys highlight correctly, your keyboard has good rollover. If some keys don't register, your keyboard may have rollover limitations in certain key zones (common on membrane keyboards).

The virtual keyboard display is fully responsive and works on mobile browsers. You can tap the on-screen keys to simulate key presses and see the key details. However, for testing a physical Bluetooth or USB keyboard connected to your mobile device, the tool works perfectly — just press the keys on your external keyboard and watch them light up on screen. The modifier indicators and detail panel are fully functional on touch devices as well. The keyboard layout may require horizontal scrolling on very small screens (under 400px width).

This tool includes a Caps Lock indicator at the top that turns red when Caps Lock is active. It updates automatically whenever Caps Lock is toggled. For Num Lock, Scroll Lock, and other lock keys, the browser's JavaScript API (getModifierState()) can detect them, and pressing those keys will show their state in the detail panel. Many modern keyboards also have LED indicators for these lock states — use this tool alongside those physical indicators to verify everything is working correctly.