Professional network timeline
Design the home timeline for a professional-networking feed with 1B users. Most users follow 200-500 connections, but some accounts (companies, influencers) have 20M+ followers. The timeline must be chronological-ish with a relevance re-rank, support sub-300ms load, and reflect a new post within ~30s for active followers.
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.
Clarify5:30 left
Estimate5:30 planned
Design16:30 planned
Deep dive13:30 planned
Failure9:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.