System designHardsd-g079

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

Question

Design the ranking system for sponsored-product results in an e-commerce search results page. The system must blend organic relevance with paid ads, run a real-time auction (advertisers bid per click), maximize a mix of revenue and user relevance, and stay under 80ms of added latency. Sellers can run thousands of campaigns; budgets must not overspend.

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.