Figma — Simple

Problem statement (interviewer prompt)

Design Figma's multiplayer canvas: many users collaboratively edit a vector design file with shapes, components, prototypes, and comments. Cover the CRDT model, server-side document state, multiplayer cursors, undo/redo, version history, and plugin runtime.

flowchart LR
  A[Editor A]
  B[Editor B]
  WS[Realtime Engine<br/>per file]
  ST[(Object tree + history)]
  CDN
  A --> WS --> B
  WS --> ST
  CDN --> A

    classDef client fill:#dbeafe,stroke:#1e40af,stroke-width:1px,color:#0f172a;
    classDef edge fill:#cffafe,stroke:#0e7490,stroke-width:1px,color:#0f172a;
    classDef service fill:#fef3c7,stroke:#92400e,stroke-width:1px,color:#0f172a;
    classDef datastore fill:#fee2e2,stroke:#991b1b,stroke-width:1px,color:#0f172a;
    classDef cache fill:#fed7aa,stroke:#9a3412,stroke-width:1px,color:#0f172a;
    classDef queue fill:#ede9fe,stroke:#5b21b6,stroke-width:1px,color:#0f172a;
    classDef compute fill:#d1fae5,stroke:#065f46,stroke-width:1px,color:#0f172a;
    classDef storage fill:#e5e7eb,stroke:#374151,stroke-width:1px,color:#0f172a;
    classDef external fill:#fce7f3,stroke:#9d174d,stroke-width:1px,color:#0f172a;
    classDef obs fill:#f3e8ff,stroke:#6b21a8,stroke-width:1px,color:#0f172a;
    class A,B,WS service;
    class ST storage;