Query understanding layer
Design the query-understanding layer that sits in front of an e-commerce search engine. Before retrieval, it must spell-correct ('blutooth speeker'), expand synonyms ('couch'->'sofa'), detect intent/category ('iphone 15 case' -> Accessories, not Phones), and strip/parse attributes (color, size, brand) from the raw query. Constraints: add under 30ms, handle 30M queries/day, and degrade gracefully when a query is gibberish.
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.
Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.