Inspiration
So this started with me wondering: how fast is my brain actually? Not in a deep philosophical way — just, like, genuinely curious. We've got apps that track everything from our steps to our sleep stages, but nobody's really thinking about reaction time as something worth checking in on. Turns out reaction time isn't just a fun party trick. It's tied to how rested you are, how focused you are, and how well your nervous system is doing its job. That felt like something worth building around.
What it does
NeuroTap measures your visual reaction time across 3 trials and gives you real feedback. You wait for a green flash, tap as fast as you can, and the app records your response in milliseconds. After three rounds it shows your average, classifies your performance, and plots your score against real population benchmarks — elite athletes, trained gamers, average adults. There's also an interactive breakdown of the 5-stage neural pathway your brain runs through on every single tap.
How we built it
Vanilla HTML, CSS, and JS — no frameworks, no backend. Timing runs on performance.now() for millisecond accuracy. The 2–5 second random delay before the stimulus is intentional: fixed delays let people anticipate instead of react, which kills validity.
Challenges we ran into
Display lag (~16.7 ms on a 60 Hz screen). Early click detection required a careful state machine to handle gracefully. And writing result copy that felt informative without being alarmist took way more iterations than the actual code.
Accomplishments that we're proud of
Getting the science right without making it feel like a textbook. The timing engine using performance.now() is the difference between a toy and something that actually measures what it claims to. And the random delay — simple idea, but it's what makes the test honest.
What we learned
Your reaction time is the sum of every biological delay from eye to finger: There's a hard floor of ~100 ms — pure biology. I also learned that RT data is right-skewed, so the median (273 ms) is more useful than the mean (284 ms) when benchmarking yourself against the population.
What's next for NeuroTap
Implementing features such as Session history, AI-powered insights via the Anthropic API, audio mode, and PDF export.
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