About CheckReaction

Why I Built This

I'm a gamer who wanted to know if my reflexes were actually improving — or if I was just telling myself that. Most reaction time tests online are single-use tools from 2003: a red-green screen, one number, and you're done. I wanted something better.

So I built CheckReaction: a platform that combines reaction time testing with cognitive training tools and free online games — all in one place. No signup, no download, no tracking. Just open the page and go.

What You Can Do Here

⚡ Test your reaction time — 5 trials, instant results with age-based benchmarks and rankings from "World Class" to "Below Average."

🧠 Train your brain — Aim Trainer for hand-eye coordination, Typing Speed Test for keyboard proficiency, Sequence Memory and Number Memory for short-term recall.

🎮 Play 17+ free games — Puzzle, action, card & board, and sports games. All embedded from trusted HTML5 game platforms, all playable instantly in your browser.

📖 Learn the science — Our blog covers reaction time research, brain health, gaming reflexes, and age-related cognitive changes — all backed by published studies.

How It's Built

Pure HTML, CSS, and vanilla JavaScript. No frameworks, no backend, no database. Hosted on Cloudflare Pages for fast global delivery. All tests and games run locally in your browser — your reaction time history is stored only on your device via localStorage.

The site is open source on GitHub: dayu2333-jinyul/reaction-time-test

Who's Behind It

Hi, I'm Jin — a developer and gamer based in China. I build fast, privacy-respecting web tools. CheckReaction is my side project, maintained in my free time. I test every feature myself (my simple reaction time averages ~220ms — drop your score in the comments if you beat me).

Got feedback, a bug report, or a game suggestion? Contact me — I read every message.