System design interview question
Design a Real-time Collaborative Document Editor with Conflict Resolution (like Google Docs at Enterprise Scale)
Design a distributed system for a real-time collaborative document editor supporting 500M monthly active users with 50M concurrent editing sessions. Users can simultaneously edit the same document with sub-second latency for cursor positions, selections, and text changes. The system must handle geographic distribution across 3 continents, guarantee eventual consistency with conflict-free collaborative editing, persist all document versions, and support undo/redo across user edits. Key constraints: P99 latency under 500ms globally, support documents up to 10MB, maintain edit history indefinitely, and handle network partitions gracefully during peer synchronization.
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