This is basically six system design questions stitched together and they want you to cover all of it.
Start by clarifying functional and non-functional requirements, then sketch a high-level architecture with core services (restaurant search, order management, dispatch, tracking, ratings). Dive deep into geospatial indexing and real-time courier dispatch, discussing trade-offs between consistency, latency, and scalability.
Pro tip: Emphasize how you'd handle peak load and failure scenarios (e.g., courier unavailability, payment failures) with graceful degradation and idempotency, showing you think beyond the happy path.
Ask questions to define functional requirements (e.g., search filters, payment methods, real-time tracking) and non-functional requirements (latency, availability, consistency). Prioritize features for an MVP.
Outline major components: API gateway, microservices (restaurant, order, payment, dispatch, tracking, review), databases, caches, message queues, and geospatial index. Draw a simple diagram.
Explain how to index restaurant and courier locations (e.g., using geohash, Quadtree, or PostGIS) and how to efficiently find nearby couriers for dispatch. Discuss real-time updates and matching algorithms.
Describe schemas for orders, users, restaurants, couriers, and reviews. Discuss consistency needs (e.g., strong for payments, eventual for tracking) and how to achieve them with databases and transactions.
Address scaling (sharding, replication, caching), fault tolerance (retries, idempotency, circuit breakers), and trade-offs (e.g., latency vs. consistency, cost vs. performance).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.