← Robinhood Interview Insights
This sounds broad until you realize how many moving parts there are.
Start by clarifying functional and non-functional requirements, focusing on core trading operations, data consistency, and scalability. Then propose a high-level architecture that separates concerns (e.g., order management, matching engine, data storage) and discuss trade-offs between consistency, availability, and latency. Finally, dive into critical components like data models, concurrency handling, and fault tolerance.
Pro tip: Emphasize the importance of idempotency and exactly-once processing in order execution to prevent duplicate trades, and discuss how you would handle partial failures in a distributed environment.
Ask questions to understand the scope: user base, order types, latency requirements, consistency needs, and regulatory constraints. Define functional (place order, cancel, view portfolio) and non-functional (scalability, availability, auditability) requirements.
Sketch the main components: API gateway, order management service, matching engine, portfolio service, market data service, and databases. Explain how they interact and the flow of an order from placement to execution.
Design schemas for orders, trades, user accounts, and positions. Choose appropriate databases (e.g., relational for transactions, time-series for market data) and discuss partitioning, indexing, and replication strategies.
Address how to handle concurrent orders, prevent race conditions, and ensure ACID properties for financial transactions. Discuss techniques like optimistic locking, distributed transactions, or event sourcing.
Explain how to scale horizontally (e.g., sharding by user or symbol), handle failures (replication, failover), and ensure low latency. Discuss trade-offs between consistency and availability (CAP theorem) and monitoring/alerting.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.