Building a Complete React Native Mobile App in One Session: 17,620 Lines of Production Code

The Challenge Transform a Next.js web application into a native mobile app ready for iOS App Store and Google Play Store submission. Not a prototype. Not an MVP. A complete, production-ready application with full feature parity. Time constraint: One working session. Result: 17,620 lines of code, 37 files, 10 screens, full CI/CD pipeline. The Stack Layer Technology Why Framework Expo SDK 54 Managed workflow, OTA updates, EAS Build Navigation Expo Router File-based routing (familiar from Next.js) Language TypeScript Type safety, IDE support Backend Firebase Auth + Firestore (existing infrastructure) Server State React Query Caching, mutations, optimistic updates Client State Zustand Minimal boilerplate, persist middleware Forms React Hook Form + Zod Validation, error handling The Secret: 94% Code Reuse The biggest accelerator wasn't a framework or library - it was architectural consistency between the web and mobile codebases. What Transferred Directly // These types work identically in