KEYTESTER PRO

Keyboard ghosting occurs when pressing multiple keys simultaneously causes an unpressed key to falsely register or prevents legitimate keys from registering (jamming). Use our tester: hold down three or four gaming keys at once (e.g., W, A, S, and D or Shift + W + Space). If all keys light up cyan without delay, your keyboard has anti-ghosting matrix protection. If one key fails to register, matrix jamming has occurred.

Anti-Ghosting refers to matrix circuit routing that prevents phantom keystrokes around commonly used gaming clusters (WASD, arrows, modifiers). N-Key Rollover (NKRO) is a hardware architecture where every individual switch is wired with an isolation diode, allowing every single key on the keyboard to be pressed simultaneously without blocking or limits.

Key chatter (double-typing) is caused by contact bounce inside mechanical switches. When metal leaf contacts touch, they physically bounce microscopically before settling. Keyboard microcontrollers run debounce filters (typically 5ms to 15ms) to ignore these bounces. If dust, liquid, or oxidation coats the contact leaf, the bouncing lasts longer than the debounce window, triggering multiple inputs for one keystroke.

The Fn key on laptop keyboards and compact 60%/TKL keyboards is intercepted directly at the hardware layer by the Embedded Controller (EC) or keyboard microcontroller firmware. It modifies the scancode of secondary keys (like media shortcuts or F-keys) before sending them over the USB/internal bus. The Fn key itself does not produce a standard HID scancode for web browsers or the operating system to detect.

Yes. KeyTester Pro listens directly to standardized DOM Level 3 scan codes (event.code), which reflect physical key positions on your hardware. It works seamlessly across Windows, macOS, Linux, ChromeOS, integrated laptop keyboards, 2.4GHz wireless dongles, and Bluetooth keyboards.

No. KeyTester Pro runs 100% client-side in your local web browser sandbox. No keystroke telemetry, input data, or diagnostic events are ever recorded, saved to cookies, or transmitted across the network. It is completely safe for verifying all standard and modifier keys.

Polling rate (measured in Hz) specifies how frequently the computer requests input updates from the keyboard controller via the USB bus. A standard office keyboard polls at 125Hz (every 8ms), whereas competitive mechanical gaming keyboards poll at 1,000Hz (1ms) or even 8,000Hz (0.125ms), significantly reducing input lag in fast-paced games.