Introduction

A local-first sync engine for TypeScript, React, and Next.js. Reads come from a local store, so the UI stays fast. Writes queue offline and sync when you reconnect. A server-sequenced log ensures every client converges.

Built on the sync architecture Linear described but never open-sourced, extended with Yjs CRDT collaboration, undo/redo, and pluggable adapters.

Key features

• Local-first reads: render from IndexedDB, no network round-trips
• Server-sequenced consistency: a monotonic syncId orders all changes globally
• MobX reactivity: only re-renders components that read changed fields
• Offline writes: a persistent outbox replays mutations on reconnect
• Rich-text collaboration: Yjs CRDT for multi-user editing
• Undo/redo: transaction-based history tracking
• Field-level conflict resolution: LWW rebase with configurable strategies
• Partial replication: load strategies control eager vs. on-demand sync
• Type-safe schema: decorators define models, typed hooks bind them to React

What you can build

Strata Sync fits products that need local-first responsiveness with predictable sync:

• Collaborative editors with offline draft support
• Task and project apps that must work on unreliable networks
• Customer-facing dashboards backed by a shared canonical state
• Mobile workflows that queue writes and reconcile after reconnecting
• Internal tools that need strong consistency without giving up responsiveness

How it works

1. Define models with decorators (@ClientModel, @Property, @ManyToOne, @OneToMany).
2. Create a sync client with storage, transport, and reactivity adapters.
3. Wrap your React tree with SyncProvider.
4. Read data with hooks (useModel, useQuery) that auto-update.
5. Write data with create, update, and delete: applied optimistically, synced in the background.

How Strata Sync compares

Feature	Strata Sync	ElectricSQL	Zero	InstantDB	PowerSync
Local storage	Built-in (IndexedDB)	Bring your own	Built-in (IndexedDB)	Built-in (IndexedDB)	Built-in (SQLite)
Conflict resolution	Automatic, field-level	Bring your own	Server decides	Server decides	Customisable
Real-time editing	Rich-text with Yjs	Not included	Not included	Not included	Not included
Offline writes	Full offline support	Bring your own	Not supported	Basic support	Full offline support
Undo / redo	Built-in	Not included	Not included	Not included	Not included

Packages

Install only the packages you need.

Package	Description
@stratasync/core	Model runtime, schema decorators, transactions
@stratasync/client	Client orchestrator, CRUD, query engine, outbox
@stratasync/react	React hooks and SyncProvider binding
@stratasync/next	Next.js App Router SSR bootstrap and serialization
@stratasync/y-doc	Yjs CRDT document and presence management
@stratasync/mobx	MobX reactivity adapter for observable models
@stratasync/storage-idb	IndexedDB storage for data, outbox, and metadata
@stratasync/transport-graphql	GraphQL + WebSocket transport for sync and mutations