Home-feed delivery at scale
Design the home-feed delivery for a creator platform where most users follow 100–500 creators, but a small number of mega-creators have 50M+ followers and post several times a day. Feeds must load in under 300ms and show new posts within seconds for normal accounts. Decide between fan-out-on-write and fan-out-on-read, justify the hybrid, and explain how you handle the mega-creator post storm without melting the write path.
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.
Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 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.