Zero

Zero is a query-driven sync engine that enables instant web applications by syncing a subset of data to the client before it's needed. Reads and writes happen against a normalized local datastore and are synced with the server continuously in the background.

website | docs | pricing page | github |

Overview

Category	Realtime
Ecosystem	Language-agnostic
Self-Hostable	Yes
On-Prem	No
Best For	startup, growth
Last Verified	2026-02-13

Strengths & Weaknesses

Strengths:

dx
performance
customization

Weaknesses:

Early stage
Query-based sync has a learning curve

When to Use

Best when:

You want query-driven partial sync
You need instant reads from local data
You're building collaborative applications

Avoid if:

You need a production-proven solution
You require full table syncing

Alternatives

electric-sql, powersync, replicache