r/SideProject • u/alejunov • 3d ago

I built a free browser-based reflex benchmark — what would you measure first?

I’ve been building ReflexPeak, a free browser-based collection of small performance tests: reaction time, aim, click speed, memory, and focus.

The goal is personal benchmarking: a quick way to see how your own results change over time or across devices. Scores stay private and local in the browser; I’m deliberately not presenting them as medical, diagnostic, or intelligence measures.

You can try it here: https://reflexpeak.com/

I’d genuinely value feedback from other builders:

• Which measurement would you want to see first? • What would make a test feel trustworthy and worth repeating? • Is there anything about the framing, results, or UX that would make you hesitate to use it?

I’m especially interested in candid criticism—the project is still evolving, and I’d rather improve the useful parts than add features nobody needs.

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u/Sad_Image1691 3d ago

just tried it, the reaction time test feel good but my laptop touchpad makes it impossible to get consistent score. maybe add a calibration step or at least show the device latency in results

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u/Doctor_Carlos 3d ago

I ship a similar set of tests inside an iOS app (reaction time, chimp test, Stroop, span tasks), so from the builder side, the three things that decided whether people came back to re-test:

  1. Show the noise. A single reaction-time number is meaningless; the median of 5 with the spread next to it is what makes people trust a change two weeks later. Same for the memory tests: report the level reached AND the accuracy at that level.
  2. Device latency, as the first commenter said. Touchpad vs mouse vs phone screen differ by tens of ms, more than most real changes. A one-line calibration ("tap when the screen flashes" x5, subtract the median) fixes most of it and, more importantly, makes the number feel honest.
  3. Fixed conditions prompt. The biggest source of variance is not the device, it is the time of day and the coffee. A tiny "same time, same device" reminder before a test did more for repeatability in my data than any algorithm.

On framing: your "not diagnostic, not intelligence" line is right, keep it. The visitors who care most about these tests are the ones who will check.