About ReactionCheck
Free browser tools for checking reactions, input devices and screens.
Who runs this site
ReactionCheck is maintained by Anil Gautam. For support, corrections or privacy questions, email anilgautamwork@gmail.com.
What the tests measure
The tools measure events exposed by your browser: response intervals, button presses, controller values and animation callbacks. The screen test displays colours for you to inspect. None can certify medical fitness, gaming ability or a hardware fault.
Each tool includes its method, limitations and steps for comparing repeated results. Browser, operating system, device settings and connection type can change a result. Use the same setup for comparisons and consult the manufacturer before attempting repairs.
Built for a quick check
No account or installation is required. Test inputs and scores are processed on your device. Optional Google Analytics measures visits and tool use only if you allow it; see our privacy details.
Report a problem
Send the page address, browser and operating system, what you expected and what happened. Device model information is optional; do not send passwords, serial numbers or private files. We use reports to investigate errors and clarify instructions.