Interactive browser keymap for mechanical and membrane keyboards. Test switch response, ghosting, rollover, and chattering in real time.
Verify your keyboard hardware matrix. Ghosting occurs when unpressed keys are falsely triggered or unrecorded during simultaneous combinations. APtester tracks multiple concurrent keydown events without artificial limits.
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.
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.
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).
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.
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.
Key chattering (key bouncing) happens when faulty mechanical switch contacts chatter repeatedly on actuation or release, registering multiple inputs for a single physical stroke. APtester flags rapid strokes under 40ms as potential switch chatter.