System designMediumsd-g075

Subject TypeaheadLevel Mid–Senior~40 minCommon in ML systems · Distributed systems interviewsIndustries Technology, Software development

Question

Design search typeahead for an online grocery store. As a shopper types, suggest products, categories, and recent items. Constraints: tolerate typos ('avacado'), rank by what's in-stock and locally available at the shopper's store, p99 under 70ms, and a catalog of 2M SKUs that varies by store (availability changes hourly).

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.