All Peripheral Tester — Free Browser Hardware Diagnostics
Diagnose keyboards, mice, displays, and audio devices directly in your web browser. 100% private, zero installation, and no keyloggers.
Online Keyboard Tester
Test switch response, N-Key Rollover (NKRO) ghosting, stuck keys, and chattering across ANSI 60%, 65%, 75%, TKL, and 100% layouts with macOS and Windows modifier toggles.
Mouse & Microswitch Tester
Inspect Left, Right, Middle, and auxiliary side buttons. Features a high-precision double-click glitch detector to diagnose worn microswitches with sub-80ms interval bounce logging.
Screen & Dead Pixel Tester
Cycle fullscreen solid red, green, blue, black, and white canvases to identify dead or stuck subpixels. Measure browser display animation smoothness with frame-timestamp estimation.
Audio & Microphone Tester
Verify stereo balance, headset channel separation (Left/Right isolation), and monitor microphone input levels in real time using the Web Audio API without saving voice recordings.
🔒 100% Local Privacy
All keypresses, button clicks, and hardware metrics are processed strictly in client-side browser memory. Zero external server transmissions, zero telemetry, zero cookies.
⚡ Low-Latency Web API
Built on lightweight modern web standards for immediate responsiveness. No heavy frameworks, no ad-bloat, and no login walls between you and your hardware diagnostics.
🛠️ Honest Hardware Metrics
Transparent browser event loop timestamps without pseudo-scientific claims. We test what browsers can measure accurately without inventing unverified hardware bus figures.
Keyboard Troubleshooting & Symptom Diagnostics
What Causes Keyboard Chattering (Double Typing)?
Keyboard chattering (or key bounce) happens when a mechanical switch's metal contact leaves vibrate or become dirty, causing a single physical keypress to register two or more characters in milliseconds. APtester flags activations occurring under 40 milliseconds as likely switch chatter.
- Press the suspected key 20 to 30 times at a consistent, normal typing rhythm.
- Observe the Event Inspector panel: check if the 'Repeat' flag is false while the interval shows under 40ms.
- Look for crimson red keycap highlights and red chatter count badges incrementing on the keycap.
- If chatter is confirmed, use compressed air to clean switch debris or consider re-soldering / hot-swapping the switch.
What is Key Ghosting and N-Key Rollover (NKRO)?
Key ghosting occurs when pressing multiple keys simultaneously causes an unpressed key to register or blocks other valid presses due to simple matrix wiring. High-performance keyboards feature anti-ghosting diodes providing true N-Key Rollover (NKRO), allowing all pressed keys to register together.
- Hold down gaming combinations such as W, A, S, D or Left Shift + Space + W simultaneously.
- Examine the 'Live Active' counter and keymap: all physically pressed keys should light up amber concurrently.
- Press additional alphanumeric keys with your remaining fingers to verify that no keypresses are blocked.
- If registrations stop after 3 to 6 simultaneous keys, your keyboard operates on standard 6-Key Rollover (6KRO).
Frequently Asked Questions
Are my keystrokes or peripheral inputs sent to any remote server?
No. APtester is built on a 100% zero-telemetry architecture. All input events (keyboard, mouse clicks, audio streams) are handled locally in your browser's execution memory and never transmitted over the internet.
Can browser testing measure true 1000Hz or 8000Hz USB hardware polling rates?
No. Modern web browsers run on the operating system event loop and cannot directly access raw hardware USB bus clocks. APtester measures accurate browser DOM event loop timestamps and intervals, not raw microsecond electrical hardware polling.
Why doesn't the Fn key or system power button register?
Hardware Fn keys and power buttons are managed directly by laptop firmware or OS kernel layers and do not emit standard browser KeyboardEvent signals. This is a deliberate platform security sandbox limit, not a hardware fault.