47. Real-Time Collaborative Whiteboard Sync Service
EXPERT
DatabaseLoad BalancingScalabilitySystem Design
The flagship design: a horizontally-scaled sync backend, its API contract, and its persistence model, all graded together.
Design the backend for a real-time collaborative whiteboard tool (think a simplified Figma/Miro sync layer). Multiple users draw on the same board simultaneously and need their changes synced. Design all three layers together: the architecture (how traffic reaches a horizontally-scaled fleet of servers), the API (how a client creates/reads/updates a board), and the schema (how boards, their participants, and periodic snapshots are persisted).