Real-time Sync Engines in 2025: LiveBlocks vs Yjs vs Automerge

Building Multiplayer Experiences

Real-time collaboration is expected in modern apps. Users want to see changes instantly, work together simultaneously, and never lose data to conflicts.

Quick Comparison

Understanding CRDTs

CRDTs (Conflict-free Replicated Data Types) enable automatic conflict resolution:

``` User A: "Hello" -> "Hello World" User B: "Hello" -> "Hello!"

Traditional: Conflict! Which wins? CRDT: "Hello World!" (merges automatically) ```

LiveBlocks: Managed Simplicity

LiveBlocks provides a complete real-time infrastructure.

Key Features

• Presence - show who's online, cursors
• Storage - persistent collaborative data
• Rooms - isolated collaboration spaces
• React hooks - excellent DX
• Managed - no infrastructure

Quick Setup

```tsx import { useOthers, useMyPresence } from '@liveblocks/react';

function Cursors() { const others = useOthers();

return others.map(({ connectionId, presence }) => ( <Cursor key={connectionId} x={presence.cursor?.x} y={presence.cursor?.y} /> )); } ```

Best For

• Quick implementation
• React applications
• Teams wanting managed infrastructure

Yjs: The Flexible Foundation

Yjs is the most popular open-source CRDT implementation.

Key Features

• Provider agnostic - WebSocket, WebRTC, etc.
• Rich text support - Quill, ProseMirror, Monaco
• Awareness - presence and cursors
• Offline support - sync when reconnected
• Mature - battle-tested

Example

```typescript import * as Y from 'yjs'; import { WebsocketProvider } from 'y-websocket';

const doc = new Y.Doc(); const provider = new WebsocketProvider('wss://server', 'room', doc);

const ytext = doc.getText('content'); ytext.observe(event => { console.log('Text changed:', ytext.toString()); }); ```

Best For

• Custom implementations
• Multiple editor integrations
• Self-hosted requirements

Automerge: Offline-First

Automerge excels at offline-first applications.

Key Features

• JSON-like API - familiar data structures
• Git-like history - branch and merge
• Offline-first - sync later
• Rust core - high performance
• Cross-platform - JS, Rust, Swift

Best For

• Offline-first apps
• Local-first software
• Document-based apps

Use Cases

Collaborative Text Editor

Recommendation: Yjs + ProseMirror

Whiteboard/Canvas

Recommendation: LiveBlocks or Yjs

Real-time Dashboard

Recommendation: LiveBlocks

Offline-First Notes

Recommendation: Automerge

Our Recommendation

• Quick start: LiveBlocks
• Flexibility: Yjs
• Offline-first: Automerge
• Edge compute: PartyKit

Explore real-time tools in our Tools directory or compare options with our Compare tool.

Sources

• LiveBlocks Documentation
• Yjs Documentation
• Automerge Documentation