REA, the viral "Reverse Engineer Anything" repo: what it does and why entrepreneurs should care

One repository has been all over developer feeds this week: REA, short for Reverse Engineer Anything, by developer morluto. On October 8–9 it hit the top of GitHub Trending, and its README now thanks users for more than 80,000 GitHub stars. One security account summed up the hype: you can give your agent a feature you like in another app, and it works out how that feature is built without ever seeing the source code.

What REA actually does

Reverse engineering means working out how software works when you only have the finished product, not the code. That used to take specialists days or weeks in tools like Ghidra or IDA Pro. REA hands much of that work to an AI agent.

It doesn't have its own decompiler. Instead, it connects your agent to tools that already exist (Ghidra, Hopper or IDA Pro for compiled programs, a Chrome-type browser for websites, JADX for Android, and others) and gives the agent simpler, higher-level actions on top of them. The agent asks REA to inspect or trace something, REA returns its findings with the evidence and the limits of each conclusion, and the agent then explains what it found or writes and tests its own version.

The README's example prompt shows the idea:

"Understand how search works in the Notes app, show me the evidence, and build a similar feature for my project."

Analysis runs on your own machine. The README points out one catch, though: whatever the agent reads still goes to your AI model provider, under that provider's data policy.

What it can look at

Static inspection of JavaScript and .NET apps only reads the files. Runtime capture actually runs the target with your user permissions, so read each guide before you use it.

Proof that it works

The project shows three detailed case studies:

• DX-Ball (Windows game): REA follows a sound call into the code that sets left/right stereo panning and rebuilds it in C. The rebuilt version passes all 3,205 test cases from the original x86 code and matches all 63 bytes of the compiled function.
• Notion (Electron app): it traces how copy and paste works, from the app's interface through Electron's internal messaging to the main process.
• TH04 (1990s Japanese PC-98 game): it recovers how the game aims rings of bullets from old 16-bit code and checks the rebuilt C++ against historical compiler output.

Impressive, but keep it in perspective. There is no standard benchmark yet, so these demos are the main evidence of how well it works.

What is new this week

REA has been around since July, but it has been moving at an unusual pace since it went viral:

• 4.1.0 (October 6): Android app analysis without a GUI, firmware analysis, read-only IDA integration, and experimental Ghidra support on Windows.
• 5.0.0 (October 7): better analysis of macOS app bundles and websites, plus tools to make minified JavaScript readable again.
• 6.0.0 (October 8): native Windows x86 apps through Ghidra, Ethereum contract bytecode, Linux crash analysis, and tracing function calls under the LLDB debugger.
• 6.1.0 to 6.3.0 (October 9–10): setup for Grok Build, results returned in one standard "Evidence" format, and many fixes.
• 6.4.0 (today): Android device control through adb, JEB support, detection of tRPC and GraphQL APIs, and setup for Pi, Hermes and Qwen Code.

The npm package rea-agents was downloaded more than 39,000 times in the week of October 3–9.

How to try it

You need Node.js 22.19 or later (or 24.11+), plus macOS 12+ or a recent Linux. Then run:

npx rea-agents setup

Setup asks which agents to connect (Claude Code, Codex, Cursor, Gemini CLI, Grok Build and others), shows you the changes it will make, backs up your existing settings, and installs matching instructions for each agent. Restart your agent and give it a prompt like the one above.

For deep analysis of compiled programs, you also need Ghidra (free), Hopper or IDA Pro installed. Setup can offer to install Hopper for you.

Why entrepreneurs should pay attention

REA isn't only for security researchers. Used carefully, it gives a small team abilities that used to need an expensive specialist.

1. Understand a competitor's feature before you build your own

A customer asks for "search like app X has" or "sync like app Y." Instead of guessing, you can have your agent study how the feature works in an app you legally use, then write a spec in plain English. You will know roughly how hard it is to build, which libraries or services it relies on, and where the tricky parts are. That makes scoping and estimating much more honest.

The goal is to understand the idea, not to copy the code. Build your own version from scratch.

2. Rescue software you own but can't maintain

Many small businesses depend on an old internal tool whose developer has left, or a program where the source code was lost. REA can help your agent work out what the program actually does, so you can document it, fix it or rewrite it in a modern language without starting blind.

3. Build integrations faster

The tools your business already uses often have no proper API documentation. REA's website and network-capture analysis can show which requests an app or site makes (it now detects tRPC, GraphQL and other API styles). That can be a starting point for connecting your own systems. Check the service's terms first: some forbid automated access to undocumented APIs.

4. Do technical due diligence

Before you buy a software product, license a vendor's SDK or acquire a small company, you can check what is really inside: which third-party libraries it ships, which servers it talks to, and whether the "AI" feature calls someone else's API. That is valuable information for any deal, and it used to need a paid consultant.

5. See your own app the way an attacker does

Point REA at your own shipped Electron, Android or web app. Attackers can read everything inside it, so check for API keys left in the bundle, hidden admin routes and endpoints you didn't mean to expose. Finding these yourself is far cheaper than finding out from a breach.

6. Spot new business opportunities

Tools like REA make some services much cheaper to offer: modernizing old software, checking app security, preserving old games, and analyzing apps for clients. If you have a technical background, there is room for a niche consultancy or a product built on top of this kind of tool.

The bottom line

REA is one of the clearest signs yet of where AI coding agents are going. They aren't only writing new code; they are learning to read software nobody gave them the source for. For developers, that means a much faster way to learn from the apps around them. For entrepreneurs, it means cheaper competitor research, easier rescue of old systems, faster integrations and better due diligence, as long as you use it on software you're allowed to analyze and build your own version instead of copying.

It is free, open source and changing daily, so it is worth trying now. Just pin a version if you depend on it.