Design Figma's Real-Time Collaborative Canvas

Problem

Design Figma's core: a real-time multiplayer canvas where many designers edit the same file simultaneously.

Requirements

Functional:

• Multiple users edit shapes/text live; see cursors
• Conflict-free concurrent edits
• Large documents render fast (pan/zoom)
• Offline edits reconcile

Non-functional:

• Many collaborators per file, large scenes
• Low-latency sync (<100ms feel)
• No lost edits

Discussion points

1. CRDT-based document model for conflict-free merges
2. WebSocket sync + presence (multiplayer cursors)
3. Client rendering (C++/WASM) and scene virtualization
4. Geometry/hit-testing performance
5. Offline reconciliation and versioning