Spent the first few minutes just trying to scope it down because bookkeeping can mean a hundred different things.
Start by clarifying the scope and requirements of the bookkeeping service, such as whether it's for personal or business use, expected scale, and key features. Then outline a high-level architecture covering data modeling, core components, and APIs, and dive into trade-offs around consistency, scalability, and security. Finally, discuss how you would ensure correctness and auditability, which are critical for financial systems.
Pro tip: Emphasize idempotency and double-entry bookkeeping as foundational principles to ensure data integrity and prevent duplicate transactions, which is crucial for a Stripe-like financial system.
Ask questions to understand the scope: single vs multi-user, expected transaction volume, required features (e.g., reporting, reconciliation), and compliance needs. This ensures you design the right system.
Propose a schema using double-entry accounting: accounts, transactions, and entries (debits/credits). Consider using an immutable ledger for auditability and support for multiple currencies.
Outline services for transaction processing, account management, and reporting. Define RESTful APIs for creating transactions, querying balances, and generating reports, ensuring idempotency keys for write operations.
Discuss trade-offs: strong consistency for financial accuracy vs eventual consistency for scalability. Consider partitioning by account or user, and using distributed transactions or sagas for cross-service operations.
Mention encryption at rest and in transit, access controls, audit logs, and compliance with standards like PCI DSS or SOC 2. Highlight the importance of data integrity and fraud detection.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.