OFFLINE-FIRST

Users aren't always online. On trains, planes, or roaming abroad — apps that don't work offline lose value in these moments. For learning and health apps especially, offline support is a differentiator.

Recommended local databases by platform:

• Flutter: Drift (type-safe SQL) or Hive (fast key-value)
• React Native: WatermelonDB for large datasets, AsyncStorage for small
• iOS: Core Data for Apple ecosystem, GRDB for SQL
• Android: Room (Jetpack) or SQLDelight (KMP compatible)

Data synchronization approaches:

• last-write-wins: simplest but risks unintended data loss
• CRDT: automatic conflict resolution based on distributed systems theory
• Custom logic: timestamps + version vectors for manual resolution
• Queue-based: buffer all changes locally, apply sequentially when online

UI patterns for communicating offline state:

• Background sync indicators: minimal distraction
• Optimistic UI: reflect locally immediately, rollback on failure
• Pending badges: explicitly show 'unsynced' state
• Offline-aware copy: 'will sync automatically' instead of 'please reconnect'

Planning offline support?

I've built multiple offline-first apps including Deckbase and EverJournal. Let's discuss your architecture.