Design a Food Delivery Platform (DoorDash)

Geo, Maps & MarketplacesHarddesign-food-delivery

Design a Food Delivery Platform (DoorDash)

Design a three-sided marketplace where an order's success depends on a restaurant, a courier, and a customer staying in sync through a multi-stage, failure-prone workflow.

Three-Sided MarketplaceBatched DispatchETA PredictionSaga Orchestration

Traffic & Capacity Estimates:

2M orders/day · 500k restaurants · 200k active couriers · 45-minute median delivery

Functional Requirements

•Show a customer nearby open restaurants with accurate menus, prices, and delivery estimates.
•Orchestrate the order through payment, restaurant acceptance, preparation, courier assignment, pickup, and delivery.
•Assign and batch couriers considering location, prep time, and multi-order routes.
•Handle cancellations, refunds, and substitutions at any stage of the workflow.

Non-Functional Requirements

•Courier assignment within 60 seconds of the restaurant accepting.
•Order state must be consistent across three apps at all times — no phantom or duplicate orders.
•Peak dinner-rush load is roughly 10x the daily mean and must not degrade assignment quality to uselessness.

Back-of-the-Envelope Math

2M orders/day with a 4-hour dinner peak carrying ~50% of volume = ~70 orders/second at peak.
Live tracking: 200k couriers * 1 update/3s = ~67k location writes/second.

Key Architectural Trade-offs

The order is a long-running saga across payment, restaurant, and logistics services — every step needs a compensating action, and 'cancelled after pickup' is a business decision encoded in code.
Batching multiple orders per courier cuts delivery cost and raises per-customer delivery time — the objective function is explicitly a trade, not an optimum.
Menu and availability data is read enormously and written rarely: aggressive caching is obvious, and a stale sold-out item is a customer-facing failure.

Click or drag a component onto the canvas, then connect the handles to draw the data flow.

3 nodes · 2 edges

Components · 35

Client & Edge4

Compute & Gateway7

Storage & Caching11

Messaging & Streaming6

Coordination & Ops5

Intelligence2

React Flow