thedatabasethat syncs

Jazz is a relational database built on real-time sync. It runs distributed across the cloud, your backend, frontend, native apps, CLIs and agent sandboxes. Mix and match ACID and local-first.

One database from the client to the cloud

Fig. 1Jazz uses the same Rust database engine core everywhere: as WebAssembly in the browser, as a native module in React Native and Node, and as the database server in Jazz Cloud and the jazz-tools CLI.

Local copies

Every client and server keeps the rows its queries need, so reads never wait on the network.

Partial sync

Only the rows a query touches move, on demand. First load is fast, later loads are instant.

One source of truth

Core authorizes every write and stores it durably. Everyone converges on the same data.

Use straight from the client as simple reactive state

Define tables and permissions in TypeScript, then query from any component. Writes apply locally at once and sync in the background.

import { useAll, useDb } from "jazz-tools/react";
import { app } from "./schema";
export function OpenTodos() {
  const db = useDb();
  const { data: todos = [] } = useAll(
    app.todos.where({ done: false }),
  );
  return todos.map((todo) => (
    <label key={todo.id}>
      <input
        type="checkbox"
        onChange={() =>
          db.update(app.todos, todo.id, { done: true })
        }
      />
      {todo.title}
    </label>
  ));
}

Fig. 2The todo example on two devices, recorded from the running app.

More examples and benchmarks →

Also for Vue, Svelte, Solid, React Native, plain TypeScript and Rust. Install guides

A database responsible for more. The hard parts of shared, live data, handled once instead of in every app.

Row-level security and per-query auth

Permissions are policies over your data and the user's JWT claims, defined in code and testable like the rest of your app.

Jazz optimizes each query together with the policies that apply to it, which removes work from your backend and gives you zero-roundtrip security.

Permissions →

Fig. 3A query and its read policy, planned together

Blobs, streams, JSON, richtext? To Jazz it's all just columns.

Jazz is designed to efficiently handle all kinds, sizes, shapes and intensities of data, while still representing everything in a simple relational model.

Durable streams? Just keep appending to a column, or stream out of one.
Binary blobs? Just put 2GB in a column, and read ranges.
Giant JSON document? Just put it in a column and stream parts with JSON pointers.
Long markdown document? It's just a very big string column.

This allows you to truly keep all data in one place, with no external links and no separate systems. And permission policies apply exactly like on normal data.

Column types →

Fig. 4Under the hood, Jazz uses prolly trees when values get large, ensuring appends, point edits, partial and streaming reads stay fast. Jazz syncs only the parts you need and any queries you run over large data operate in a streaming fashion.

Local-first data with tunable consistency

Like an embedded database, Jazz brings durable data directly into your frontend and backend, and syncs it to the cloud. It feels like shared reactive state that abstracts away networking.

Jazz is eventually consistent by default. Where transactionality matters, trade latency for globally consistent transactions, in the same database.

How sync works →Durability tiers →

Fig. 5A write's local state, its sync message, and its confirmed fate

Real-time collaboration and deep edit histories

People and agents now edit the same data at a much higher rate, and you need to reason about it afterwards.

Jazz gives you flexible, branch-like views over your data. Build anything from drafts to complex git-like workflows on them, including permissions over branches.

Branches →Edit metadata →

Fig. 6The history of one row, with a draft branch

Fluid schema evolution for fast teams

Instead of stop-the-world migrations, Jazz migrations are live compatibility layers that translate between the versions of your app.

Old clients keep working, new features ship without complicated rollouts, and apps with many feature flags stay safe to change.

Migrations →

Fig. 7One raw table, read as two app versions through migration lenses

Slims your backend and simplifies your infra

Networking, permissions, auth integration and a collaboration-native data model are standard in Jazz, so your backend holds business logic instead of glue.

Jazz also covers roles that usually need their own infrastructure or vendors: blob storage, file and image CDN, durable streams and real-time message queues.

Server setup →Auth providers →Permissions →How sync works →

Fig. 8What moves out of your code into Jazz

Self-host or use Jazz Cloud

The single-tenant Jazz server will always be open source and is easy to self-host. Jazz Cloud is the same database, running on global infrastructure tailored for it.

As developers, we hate pricing that makes limiting assumptions about your app and your users, so we bill across simple metrics for the things that are irreducibly hard.

Self-hosted	Jazz Cloud	Enterprise
Setup
One open-source, single-tenant server binary	Zero config; create an app from the CLI or dashboard	Dedicated deployment or bring your own cloud, set up with you
Topology
Runs where you deploy it	Globally distributed and geo-optimized	Regions and data residency to your requirements
Reliability
You operate backups and failover	Fault-tolerant, with backups included	Uptime SLA and direct support
Scaling
Size the instance yourself	Scales more granularly than instance-based databases	Capacity planned with you
Compute
Your own servers; one instance runs a whole app	$0.039 per hour of 2GB RAM instance Auto-scaling available soon. 1GB RAM instance always included.	Volume pricing
Storage
Your own disks	$0.45 per GB/month Includes backups and caches. 1GB/month included.	Volume pricing
Egress
Your hosting provider's rates	$0.09 per GB out Passed through at cost. 5GB/month included.	Volume pricing
How to self-host	Generate API key	Book a call

Estimate your Jazz Cloud bill

Move the sliders to match your app. The estimate uses the Jazz Cloud prices above.

Monthly active users1k MAUs

Frequency of useDaily

Real-time profileMostly form-like apps

Blob storage per user

Daily estimates about 20 visits per monthly active user across 20 active days each month.

Mostly form-like apps assumes ~3 minute sessions over the active window, plus a short idle shutdown grace period.

Cost per user / mo

$0.02

Based on 1k monthly active users

Estimated monthly bill

$22.9

Rough self-serve estimate based on the draft public meters on this page. Enterprise contracts can still diverge.

From the blog

All posts →

Apr 17, 2026 · Anselm Eickhoff
The four fresh ideas behind Jazz
Why local-first, per-query auth, deep histories, and fluid migrations come together in Jazz
Apr 17, 2026 · Anselm Eickhoff
What is Jazz?
(a local-first relational database)
Apr 17, 2026 · Anselm Eickhoff
What we learned from classic Jazz
The main lessons from Jazz v0.x, why Jazz v2 changed so much, and how migration works

npm create jazz

Scaffold a synced app in one command, with auth and hosting set up for you.

$ npm create jazz

Read the quickstart or join the Jazz Discord.