Code Room
System designHard
Question
Design the order-batching and courier-assignment engine for a food-delivery marketplace handling 500k concurrent orders at dinner peak. The engine must assign couriers to orders (and batch multiple orders onto one courier) while balancing delivery time, courier earnings, and food freshness, recomputing assignments every few seconds as new orders and couriers arrive. Cover the data model, the assignment algorithm, and how you avoid thrashing already-committed assignments.
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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