Detecting Rooted & Jailbroken Devices in React Native — How I Built It and What I Learned

I've been working on a React Native security library for the past few months. Not because there wasn't anything out there, but because most existing solutions were either outdated, not maintained, or didn't support the New Architecture. So I built react-native-root-jail-detect from scratch — native Swift for iOS, Kotlin + C++ for Android, full TurboModules and Fabric support. Here's what I learned building it. The Problem With Simple File Checks Most jailbreak detection libraries do something like this: let jailbreakPaths = [ "/Applications/Cydia.app" , "/bin/bash" ] return jailbreakPaths . contains { FileManager . default . fileExists ( atPath : $0 ) } This works — until it doesn't. /bin/sh exists on stock iOS. /var/log/syslog exists on non-jailbroken devices. And on the simulator, the entire macOS filesystem is exposed, so paths like /usr/bin/ssh and /etc/ssh/sshd_config all exist on a perfectly clean machine. The fix isn't just a better list of paths. It's knowing which paths are sa