Flash Clapper

A simple browser-based tool to measure hardware latency of your camera and microphone for synchronization in streaming. No account, no backend.

Try it live: klippros.com/tools/flash-clapper

Privacy

All processing happens in the browser. Your audio and video never leave your device.

How to use

1. Allow camera and microphone access when prompted.
2. Use a dark room so the screen flash is easy for your webcam to detect.
3. Pick your camera and microphone, then set the mic threshold so mouse clicks register on the meter.
4. Click Start test, then click your mouse anywhere on screen. The app flashes white and measures how long your webcam and mic take to react.
5. Run several tests (five or more is ideal). Check the median row and remove any outlier results.
6. Click Show streaming sync settings for OBS or generic offset guidance to apply in your streaming software.

For more detail on how the measurement works, see the About page in the app.

Development

Prerequisites: Node.js, pnpm 10+.

pnpm install
pnpm dev      # http://localhost:5173
pnpm build
pnpm preview

Contributing

See AGENTS.md for project conventions.

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© 2026 Klippros Studios AB · GitHub