System designMediumsd-g146

Subject Location trackingLevel Mid–Senior~40 minCommon in Distributed systems interviewsIndustries Technology

Question

Design a real-time location-sharing feature (friends/family see each other's live location on a map) for 100M users in groups/circles, where a viewer should see a member's marker move within a few seconds of the member moving. Cover how updates fan out to viewers, how you handle the social graph, and privacy/permission controls.

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.