Local-First - HelpMeTest

Local-First

Replicache Testing Guide: Mutations, Rebase, Conflict Resolution, and Offline Testing

Replicache is the local-first sync framework that made optimistic UI updates on top of server-authoritative state mainstream. Its core bet: every mutation applies optimistically on the client, gets rebased when the server responds, and conflict resolution happens through a deterministic rebase algorithm. Testing this correctly requires understanding the

Testing

Testing ElectricSQL: Local-First Sync, Conflict Resolution, and Offline Mode

ElectricSQL takes a fundamentally different approach to application data. Rather than fetching data on demand, it syncs a subset of your Postgres database into a local SQLite store and keeps it live. Your application reads from local SQLite—always fast, always available—while Electric handles bidirectional sync in the background.

Local-First

PowerSync Testing Guide: Offline-First, SQLite Sync, and Schema Testing

PowerSync takes a different approach to local-first sync: it works with your existing Postgres (or MongoDB) backend and SQLite on the client, replicating rows automatically based on sync rules you define. Testing PowerSync means verifying that sync rules route the right data to the right users, upload queues handle