Offline-First Apps & Data Synchronization

Apps that keep working in basements, warehouses and on rural roads: a local database as the source of truth, a sync engine that survives retries, and conflict rules agreed up front.

An offline-first app reads from and writes to a local database first and treats the network as something that comes and goes. Done well, users never wait on a spinner for data they already have. Done badly, they get duplicate records and edits that silently vanish. My usual design: SQLite on the device as the source of truth for the UI — through Room, GRDB, drift or a React Native SQLite library — with the schema and migrations versioned like server code. An outbox of pending changes, each with a client-generated ID and an idempotency key, so a request that timed out can be retried without…