The Repo
REA (Reverse Engineer Anything) lets your AI coding agent look at any app, work out how a feature actually works, show you the evidence, and then build you the same thing. It doesn't need the source code. It's free and open source.
Install It — 60 Seconds
Easiest way: copy the repo link above, paste it into your favourite AI coding agent — Claude Code, Cursor, Codex, Gemini CLI, Grok — and tell it to install REA. The docs tell it exactly what to run, so it sets itself up.
Doing it yourself:
- Make sure you have Node.js installed (v22 or newer).
- Open your terminal and run:
npx rea-agents setup - Pick your agent, then approve the changes.
- Restart your agent. That's it.
Now just ask it in plain English:
"Understand how search works in the Notes app, show me the evidence, and build a similar feature for my project."
Swap "Notes app" for whatever you want to pull apart.
Interesting Things To Point It At
The obvious use is copying a feature. The more interesting use is understanding why something works:
- What makes an app addicting — have it map TikTok's or Instagram's feed loading, prefetching and refresh triggers, then explain the loop that keeps you scrolling.
- The onboarding that converts — pull apart how Duolingo or Notion sequences its first-run experience and where it asks for the commitment.
- That one animation you can't replicate — find the exact easing, timing and trigger behind a UI interaction you love.
- Hidden pricing and paywall logic — see how an app decides when to show you the upgrade screen.
- Why one app feels fast and yours doesn't — Spotifast exists because someone did exactly this to Spotify and got it running in 200MB of RAM.
- Notification timing — when apps actually choose to ping you, and what triggers it.
- A game you grew up with — the original Halo got cracked open and now runs in a browser with 128-player lobbies.
Humans have always copied what works. We just never had a way to do it this fast.
Reverse Engineer Your Life Next
Same idea, bigger target. If you want to spend 100% of your time and energy doing what you actually love, come learn the 90% AI / 10% Human system in our free workshop.