Code Room
System designHard
Question
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.
Learn the concepts
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Run or narrate your approach, then ask the coach.