Collaborative editing with Yjs

Regular fields use server-sequenced LWW sync. Collaborative fields use Yjs CRDTs for character-level merge: no central server needed for conflict resolution.

Architecture overview

Each client binds to a local Yjs document that syncs through the shared WebSocket.

Copyflowchart TB
    subgraph Client A
        EA[Editor] --> YA[Y.Doc]
        YA --> WA[WebSocket]
    end

    subgraph Client B
        EB[Editor] --> YB[Y.Doc]
        YB --> WB[WebSocket]
    end

    subgraph Server
        WA --> SS[Sync Server]
        WB --> SS
        SS --> Redis[(Redis)]
        SS --> PubSub[PubSub]
        PubSub --> SS
        SS --> DB[(Database)]
    end

• Demand-driven sessions: Live editing starts only when 2+ users view a document and one is editing, cutting server usage by ~96%.
• Shared WebSocket: Yjs updates piggyback on the existing sync connection.
• Standard sync fallback: If live editing goes down, no data is lost.