The weird part wasn't the question itself, it was the pacing.
Start by clarifying the scope and requirements of the donation system, such as whether it's for Lyft rides, charitable giving, or a general platform. Then outline a high-level architecture covering core components like user management, payment processing, and donation tracking, and dive into trade-offs for scalability, consistency, and security.
Pro tip: Emphasize idempotency and exactly-once processing for donations to prevent duplicate charges, and discuss how you'd handle reconciliation with external payment providers—this shows you understand real-world financial systems.
Ask questions to understand functional and non-functional requirements, such as expected scale, supported payment methods, and whether donations are one-time or recurring.
Sketch the main components: API gateway, user service, donation service, payment service, database, and message queue for asynchronous processing.
Detail the donation flow, including validation, payment authorization, idempotency, and updating donation records. Discuss data models for users, donations, and transactions.
Discuss choices like SQL vs NoSQL, synchronous vs asynchronous processing, and how to scale horizontally. Consider consistency models and failure handling.
Cover PCI DSS compliance, encryption, fraud detection, and audit logging. Mention how to handle sensitive data and prevent abuse.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.