How to Crack System Design Interviews at FAANG

The Anatomy of a System Design Interview

System design interviews can be intimidating because they are open-ended. There is no single "right" answer. Instead, interviewers are looking for your ability to communicate, make trade-offs, and scale a system.

Step 1: Clarify Requirements

Never start drawing architecture diagrams immediately. Spend the first 5-10 minutes asking clarifying questions.

• What are the core features?
• What is the expected scale (DAU/MAU)?
• Is the system read-heavy or write-heavy?

Step 2: High-Level Design

Draw the happy path. Show how the user interacts with the API gateway, the application servers, and the database. Keep it simple initially.

Step 3: Deep Dive and Scale

Once the high-level design is approved, pick a specific component and dive deep.

• Database: Should we use SQL or NoSQL? How do we shard?
• Caching: Where can we add Redis to reduce latency?
• Asynchronous Processing: Use message queues (Kafka, RabbitMQ) for heavy background tasks.

Conclusion

Always communicate your trade-offs. If you choose NoSQL, explain why you are sacrificing ACID compliance for horizontal scalability. A good interview is a collaborative discussion, not a solo presentation.