System designHardsd-p024

Subject Ml system designLevel Senior–Staff~45 minCommon in ML systems interviewsIndustries Technology, Software development

Question

Design the serving system for a product recommendation model: it must return personalized recommendations within ~100ms and stay fresh as user behavior changes.

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.