How does Convex compare to a Postgres-based sync engine?

Convex brings its own database and runs writes as server functions. Pick it to have one product own the backend. Pick a Postgres-based engine when the database is already yours.

What is the difference between Strata Sync and Zero?

Zero adds zero-cache and its own query language. Strata Sync adds routes to your app and uses model classes. Zero is the better pick if you want queries as the main abstraction.

Is ElectricSQL a full sync engine?

It streams filtered Postgres data to clients and leaves writes to your own API. The outbox, retries and conflict handling are yours to build.

Which sync engines handle collaborative text editing?

None of them ship it. Strata Sync includes Yjs documents and presence for text fields. The others expect you to add a CRDT layer.

Sync engines compared: Strata Sync, Zero, Electric, Convex

The open-source sync engines differ on three things: whether they own your database, whether you run an extra service, and whether writes go through them or your own API.

Three questions that separate them

Does it own your database? Convex and InstantDB bring their own. Electric, Zero, PowerSync and Strata Sync use the one you have.
Does it add a process to run? Zero, Electric and PowerSync each run a service. Strata Sync adds routes to your app.
Do writes go through it? Electric leaves the write path to you. Convex, Zero and Strata Sync ship one.

Side by side

Sync engines compared on data, extra services, writes, conflicts, and text and undo
	Strata Sync	Zero	ElectricSQL	Convex	InstantDB	PowerSync
Your data	Your Postgres, in your app	Your Postgres	Your Postgres	Convex's database	Instant's database	Your database
Extra service	None	zero-cache	Electric	Convex cloud	Instant cloud	PowerSync
Writes	Built in	Custom mutators	Your own API	Server functions	Built in	Your own handler
Conflicts	Server log, per-field rebase	Server-authoritative	Replication stream	Transactional	Server-authoritative	Checkpoints
Text and undo	Both built in	Bring your own	Bring your own	Bring your own	Bring your own	Bring your own

Columns describe each project’s documented defaults as of September 2026. If one has moved on, open a pull request.

Convex

The one that changes the shape of your backend rather than attaching to it: a managed reactive database, reactive queries and server functions. A strength when you are starting fresh. The wrong fit when the Postgres already exists and has to stay where it is.

Zero

Runs zero-cache beside your Postgres and gives you ZQL, with server-authoritative rebasing. Pick it to think in queries. Pick Strata Sync to declare model classes and not add a process. The detailed comparison says when Zero is the better answer.

ElectricSQL

Streams filtered Postgres data to clients and deliberately leaves writes to your API, which keeps it small. The outbox, retries and conflict handling are yours to build.

InstantDB and PowerSync

InstantDB pairs a hosted database with a built-in write path for getting a collaborative app up fast. PowerSync syncs an existing Postgres or MongoDB to on-device SQLite, with strong React Native support, and is the most mobile-oriented of the group.

Where Strata Sync fits

It implements the architecture Linear described: one server, one counter, one order every client replays, with conflicts resolved per field. It ships the parts usually left to you, including the outbox, rebase, sync groups, undo and Yjs text, and runs inside your Fastify app against your Postgres. It is younger than Electric or Convex and built by one author plus contributors. If you want a vendor whose whole company is this, that is a real argument for the others.

Common questions

Get started

One command. It scaffolds a working app with the sync server wired up.

npx stratasync init my-app

Read the docs