Visual product search
Design a visual / image-similarity search system where users upload or tap a photo and get visually similar products to buy. Catalog: 300M product images, must return in under 300ms, support metadata filters (price, in-stock, category) combined with visual similarity, and stay fresh as new products are added 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.
Clarify6:00 left
Estimate6:00 planned
Design18:30 planned
Deep dive14:30 planned
Failure10:00 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.