System designHardsd-p112

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

Question

Design an online optimization platform that uses multi-armed bandits to automatically allocate traffic to the best-performing variant (which headline or layout converts best), learning in real time.

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.