Reaction

The pad goes Blaze, you tap. Five taps, averaged, in milliseconds — the same simple visual reaction protocol sleep researchers have leaned on for decades, in its browser Sunday best. Jump early and the round laughs at you.

Reaction time is the classic canary for sleep debt and the classic beneficiary of caffeine — which is exactly why it’s worth retesting across a week rather than once. Your number includes your screen and your hardware, so duel your own best on the same device. The percentile compares you against public reaction-test aggregates (median 273 ms across 81M+ browser clicks) until our own player distribution takes over. See what actually shifts it with the sleep calculator and the caffeine calculator. Then try Recall or Track, or head back to the Lab.