Online Keyboard Tester

Instant, zero-telemetry browser diagnostic utility for mechanical and membrane keyboards. Test key rollover (NKRO), stuck keys, switch chattering, and latency across ANSI 60%–100% and Mac/Win layouts with 100% client-side privacy.

Esc

F10

F11

F12

PrtScn

Scroll Lock

Pause

Backspace

Insert

Home

Page Up

Num Lock

−

Tab

{[

}]

Delete

End

Page Down

Caps Lock

Enter

Shift

↑

Enter

Ctrl

Win

Alt

Win

Ctrl

←

↓

→

How to Test Your Keyboard

Press Any Key: Press any physical key on your keyboard. The corresponding keycap on the interactive virtual layout will highlight in real time to confirm registration.
Verify Color States: A key lights up in amber while actively held down (Active) and transitions to mint green once successfully released (Tested).
Test Simultaneous Key Presses (NKRO): Press 3 or more keys simultaneously (such as gaming clusters like W-A-S-D or Shift-Ctrl-Space) to verify if your keyboard matrix supports multi-key rollover without ghosting.
Check Switch Chatter: Watch the event inspector interval delta. Rapid secondary registrations under 30–50ms without physical release indicate switch bounce or chattering.
Select Your Layout: Use the layout selector to toggle between standard ANSI 100%, Tenkeyless (87%), 75%, 65%, or compact 60% layouts, as well as Windows and macOS modifier legends.

Key Diagnostic Features & Capabilities

N-Key Rollover & Anti-Ghosting Verification

Verify your keyboard hardware matrix. Ghosting occurs when unpressed keys are falsely triggered or unrecorded during simultaneous combinations. APtester accurately tracks multiple concurrent keydown events without artificial limits.

Switch Chattering & Double-Press Detection

Mechanical switches degrade over time due to contact oxidation or spring fatigue, causing a single keypress to register multiple times. Registrations under 40ms are flagged immediately with a red chatter badge.

Windows & macOS Modifier Mapping

Toggle between Windows (Win/Alt/Ctrl) and macOS (Command/Option/Control) legends seamlessly. Matching is performed on physical hardware scan-codes (KeyboardEvent.code), preserving spatial key positions.

Technical Scope & Privacy Guarantees

Zero-Telemetry Client-Side Processing: APtester is built with privacy as a foundational principle. Keystrokes, modifier states, and timing metrics are processed strictly inside your browser's local JavaScript execution context. No input data, event logs, or device fingerprints are ever transmitted across the network.

Browser Diagnostic Boundaries: In compliance with web platform security standards, browser tests evaluate DOM KeyboardEvent inputs. APtester measures accurate event timestamp deltas within the browser event loop. Browser sandboxes cannot measure raw hardware USB electrical polling rates, switch spring resistance, or intercept OS-reserved hardware hotkeys (such as certain laptop Fn-row combinations and system power buttons).

Frequently Asked Questions

Why does APtester not send keystrokes to a server?

Sending keystrokes over the internet creates an inherent keylogging and privacy risk. APtester runs 100% locally in your browser sandbox, guaranteeing that sensitive key presses, passwords, or personal habits never leave your device.

Can I test function keys (Fn) on laptop keyboards?

Most laptop Fn keys are hardwired at the hardware/embedded controller (EC) level and do not emit standard HID scancodes to the operating system or browser unless combined with mapped hotkeys. Standard F1–F12 function row keys are fully testable.

What is key chattering?

Key chattering (key bouncing) happens when a faulty mechanical switch contacts chatter repeatedly on release or actuation, registering multiple inputs for a single physical stroke. APtester flags rapid strokes under 40ms as potential switch chatter.