System designHardsd-g071

Subject RankingLevel Senior–Staff~55 minCommon in ML systems interviewsIndustries Technology, Software development

Question

Design the search-ranking system for a vacation-rental marketplace. A query (location + dates + guests) retrieves up to 10k eligible listings; you must rank them by predicted booking probability personalized to the user. Constraints: ranking adds at most 150ms over retrieval, the model is retrained nightly, and ranking must be consistent within a paginated session (page 2 follows page 1).

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.