Home page module ranking
Design the system that ranks the *rows/modules* of a personalized home page (e.g. 'Continue watching', 'Because you watched X', 'Trending', 'New releases', 'Top picks') per user — deciding which row goes at the top and which gets dropped — rather than ranking items within a row. There are ~40 candidate modules, you show ~10, and you want to maximize engagement while continuously learning which modules work for which users, at 100M users with a < 80ms budget. How do you score and order the modules, and how do you keep learning online?
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.