Problem Understanding
Restate the problem in your own words.
Design DoorDash (Food Delivery)
Design a DoorDash-class food delivery platform: an eater browses menus, places an order, and the system finds a restaurant to accept and a courier to pick it up and deliver — with live ETA and tracking the whole way. The architecture is a three-sided marketplace with two stages of matching (order → restaurant, then order → courier) and an order state machine that composes both sides. ETA prediction is itself a sub-system that estimates restaurant accept time + prep time + courier pickup + drop time. Dynamic batching (one courier carries two nearby orders) is the deep-dive that separates correct designs from optimal ones.
- DoorDashUS-dominant food delivery; ~2 B+ orders / yr; pioneered batching.
- Uber EatsCross-pollinates with Uber's ride dispatch; shares the courier geo-index pattern.
- Swiggy / ZomatoIndia-scale; hyperlocal delivery hubs; cloud kitchens are a separate tenant model.
- DeliverooEU-focused; same three-sided shape; stronger emphasis on dark kitchens + rider scheduling.
Your task: read the problem above, then write what the system is, who uses it, the rough scale, and the headline UX expectation — in your own words. Submit for AI review when you're ready.
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