System designHardsd-g512

Subject Collaborative editingLevel Senior–Staff~50 minCommon in Distributed systems interviewsIndustries Technology, Computer games, Software development

Question

Design real-time multiplayer cursor and selection sync for a collaborative canvas/design tool (think Figma-style). 200 users in one file, each moving a cursor and dragging objects; everyone must see everyone else's cursor at ~60fps-feeling smoothness with sub-100ms perceived latency, over the public internet with varying RTTs. Object edits must converge; cursor positions are ephemeral.

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.