rnsec is a zero-configuration static analysis security scanner for React Native and Expo applications. It scans JavaScript/TypeScript, XML, plist, and JSON files for over 85 security rules covering storage, network, authentication, cryptography, logging, Android/iOS platform issues, and supply chain risks. The tool uses Babel AST parsing and regex pattern matching to detect hardcoded secrets, insecure configurations, and common vulnerabilities. It generates HTML, JSON, and Markdown reports, supports CI/CD integration with changed-files scanning, and can post results as GitHub PR comments. The architecture is a monolith CLI application built with Commander, with a modular rule engine that registers scanner groups. The codebase is well-structured, TypeScript strict, and includes comprehensive tests for all rules.