Building Offline-First Web and Mobile Applications

Introduction: The Offline-First Imperative

Users expect applications to load instantly and work smoothly even on airplanes or in subway stations. Offline-first apps use local data storage as the primary source of truth, syncing updates in the background.

Architecture of Offline-First Apps

1. Local Storage Engines

Use SQLite or RxDB on mobile, and IndexedDB or WatermelonDB on web, to read and write database records locally.

2. Synchronization Protocols

Implement background sync engines that track local mutations and resolve server conflicts (e.g., Last-Write-Wins, CRDTs).