Real-Time Collaboration (WebSocket + CRDT + React + PostgreSQL) overview

An architecture for building collaborative editing and real-time shared state applications. WebSocket connections provide bidirectional communication between clients and server, CRDT libraries like Yjs handle conflict-free merging of concurrent edits, React renders the live UI, PostgreSQL persists document state, and Redis serves as the pub/sub backbone for broadcasting changes across server instances. The key design challenge is reconciling optimistic local edits with remote changes without user-visible conflicts. Yjs provides a mature CRDT implementation that handles text, JSON, and array types with automatic conflict resolution. The server acts as both relay and persistence layer, storing periodic snapshots and incremental updates. This stack powers document editors, collaborative whiteboards, shared spreadsheets, and multiplayer design tools. The primary tradeoff is increased complexity in state management and debugging compared to request-response architectures.