System design interview question
Design a Real-time Collaborative Document Editor with Operational Transformation (like Google Docs at scale)
Design a globally distributed, real-time collaborative document editing platform supporting 500M registered users with 50M concurrent active documents. Users must see edits from collaborators within 200ms latency, with strong consistency guarantees for document state across regions. The system handles 100K concurrent edits per second, must persist all document versions for audit trails, and support instant conflict resolution when multiple users edit the same section simultaneously. Consider geographic distribution across 3 major regions, recovery from network partitions, and maintaining causal ordering of edits across asynchronous replication.
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