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Architecture Reference Blueprint

Multiplayer Real-Time Whiteboard with CRDTs & WebSockets

Build collaborative multiplayer web applications (like Figma or Miro) with Conflict-Free Replicated Data Types (CRDTs) and optimistic canvas rendering.

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System Constraints

Non-Negotiable Architecture Constraints

✓Sub-50ms latency for peer-to-peer multiplayer cursor and drawing synchronization
✓Offline-first editing with automatic mathematical conflict resolution upon reconnection
✓Support 100+ concurrent collaborators on a single shared infinite canvas
✓Efficient binary state delta encoding minimizing WebSocket bandwidth

Component Topology

System Components & Technologies

Modular subsystems designed with decoupled responsibilities, clear contracts, and scalable storage layers.

3D Isometric Architecture

Multiplayer Real-Time Whiteboard with CRDTs & WebSockets Stack Topology

Live Telemetry Active
Tier 1: CollaborativeTier 2: CRDTTier 3: MultiplayerTier 4: Document
01

Collaborative Canvas UI

< 15ms
Role: High-performance WebGL/Canvas rendering of shapes and user presence cursorsNext.js + PixiJS / React Flow
02

CRDT State Layer

< 35ms
Role: Managing shared document mutations and conflict-free mergingYjs / Automerge
03

Multiplayer Signaling Server

< 5ms
Role: Room-based WebSocket coordination and ephemeral presence broadcastingNode.js (uWebSockets.js) / Cloudflare Durable Objects
04

Document Persistence Tier

< 1ms
Role: Storing binary CRDT state vectors and document snapshotsPostgreSQL / AWS S3
Subsystem 01

Collaborative Canvas UI

High-performance WebGL/Canvas rendering of shapes and user presence cursors

Production Stack:

Next.js + PixiJS / React Flow

Subsystem 02

CRDT State Layer

Managing shared document mutations and conflict-free merging

Production Stack:

Yjs / Automerge

Subsystem 03

Multiplayer Signaling Server

Room-based WebSocket coordination and ephemeral presence broadcasting

Production Stack:

Node.js (uWebSockets.js) / Cloudflare Durable Objects

Subsystem 04

Document Persistence Tier

Storing binary CRDT state vectors and document snapshots

Production Stack:

PostgreSQL / AWS S3

Data Lifecycle

End-to-End Data Flow Sequence

1

User opens shared canvas; WebSocket connects to assigned Cloudflare Durable Object room coordinator.

2

Room coordinator sends binary Yjs state vector; client loads initial canvas state into memory.

3

User moves a shape; client updates local Yjs document optimistically and renders immediately in 16ms.

4

Yjs encodes binary delta update and broadcasts to all room peers over WebSockets.

5

Peer clients receive delta and merge updates mathematically using CRDT logic with zero merge conflicts.

Reliability & Resilience

Failure modes & automated mitigations

Failure Mode 01

WebSocket Connection Drops in Mobile Browsers

Mitigation Architecture

Buffer local edits in IndexedDB; Yjs automatically reconciles offline mutations upon reconnection.

Failure Mode 02

Large Document Memory Bloat

Mitigation Architecture

Periodically compact CRDT transaction history into unified document snapshots stored in S3.

Failure Mode 03

Cursor Presence Bandwidth Floods

Mitigation Architecture

Throttle cursor coordinates to 30fps and broadcast as lightweight ephemeral arrays without persisting to disk.

Architecture FAQs

Frequently asked blueprint questions

Operational Transformation (used by Google Docs) requires a central server to order operations. CRDTs resolve conflicts mathematically on any device without central server coordination.

Yjs uses Lamport timestamps and unique client IDs to deterministically order concurrent edits, guaranteeing all users converge to the identical state.

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