Start by clarifying requirements and scale, then design a high-level architecture that decouples request submission from hero dispatch using a queue and matching service. Focus on core components like request intake, hero availability, matching algorithm, and notification, while discussing trade-offs around consistency, latency, and scalability.
Pro tip: Frame the problem as a two-sided marketplace with real-time constraints, and explicitly call out how you'd handle race conditions when multiple heroes try to accept the same request—this shows you think about concurrency and reliability, which is crucial for Stripe's payment systems.
Ask questions to understand functional and non-functional requirements: expected request volume, number of heroes, geographic distribution, latency needs, and consistency guarantees. Define the MVP scope and what can be relaxed.
Sketch the main components: API gateway for request submission, a queue or event stream for incoming requests, a matching service that pairs requests with available heroes, a hero availability service, and a notification service. Explain data flow and interactions.
Detail the matching algorithm (e.g., based on proximity, hero skills, and current load) and how to handle concurrent acceptances using optimistic locking or a first-write-wins approach. Discuss how to ensure exactly-once assignment.
Propose schemas for requests, heroes, and assignments. Choose appropriate databases (e.g., relational for transactions, geospatial index for location) and discuss consistency vs. availability trade-offs.
Address scaling (sharding, partitioning), fault tolerance (retries, dead-letter queues), and monitoring. Discuss trade-offs like latency vs. consistency, and how to evolve the system over time.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.