youtubeJuly 30, 2025
Sync Engines and Local Data
Wes and Scott explore local-first sync engines — why they make apps feel fast, and how LiveStore, Zero, Instant DB, Convex, ElectricSQL, and PowerSync each approach the problem differently.
Timestamps
| Time | Topic |
|---|---|
| 00:00 | Intro — what makes apps feel fast |
| 08:23 | livestore — deep dive |
| 18:01 | Zero (Replicache) — how it works |
| 21:58 | instantdb — overview and trade-offs |
| 24:43 | convex — reactive backend |
| 27:54 | ElectricSQL — Postgres sync |
| 29:48 | powersync and PartyKit |
| 30:51 | How to choose the right sync engine |
Key Takeaways
Why Local Data Matters
Apps that read and write to local data feel instant. No loading spinners, no waiting for network round-trips. The sync engine handles pushing changes to the server in the background.
Sync Engines Compared
- LiveStore — client-side SQLite with event sourcing, works well with frameworks like Vue and React
- Zero — from the Replicache team, server-authoritative sync with partial replication
- Instant DB — Firebase-like DX with real-time sync and relational queries
- Convex — reactive backend with built-in sync, functions run server-side
- ElectricSQL — syncs a subset of your Postgres database to the client
- PowerSync — Postgres-based sync with offline support, good for mobile
Choosing the Right Engine
The choice depends on your existing stack, how much control you need over conflict resolution, and whether you want a client-first or server-first architecture. There is no single "best" engine — each makes different trade-offs around consistency, flexibility, and developer experience.