Design Restaurant Search Ranking and Its Online Experiment

Asked at DoorDash · System Design for ML · Difficulty: Hard · Last asked Nov 7, 2026

Design the ranking system behind restaurant search in a food-delivery marketplace, and design the online experiment that decides whether a new ranker ships. A customer types a query such as "pad thai" or "sushi", and the system must return an ordered list of restaurants that this customer, at this place and time, is most likely to order from. The marketplace has three sides, customers, restaurants and couriers, so a change to the ranking also changes how much work the couriers receive.

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