FAANG Interview Fast Track

The five systems that appear most in senior engineering loops — from a warm-up URL shortener to a full fan-out social feed and a payment system that cannot double-charge.

After this path you will be able to

Walk into a system design interview with a repeatable framework: clarify requirements, estimate scale, sketch the high-level design, identify the two or three hard problems, and defend your trade-offs.

Interview approach for this path

1.Spend the first 5 minutes clarifying requirements and asking about scale: DAU, read/write ratio, latency SLA. Don't skip this.
2.Do a back-of-envelope estimate before drawing anything. Show your math for storage and QPS to validate your design choices.
3.State your high-level design in one sentence before drilling into components. The interviewer needs to know where you're going.
4.Identify the two or three genuinely hard problems for this system and say them out loud. Don't wait for the interviewer to probe.
5.For every major component, explain why you chose it. 'I'd use Cassandra here because the write throughput exceeds what Postgres can handle on a single node' beats 'I'll use Cassandra.'
6.Address failure scenarios proactively: what happens if the cache is cold, the queue backs up, or the primary DB fails?
7.Close by discussing trade-offs. Good candidates say what they'd do differently with more time or different constraints.

Systems in this path

5 total

Concepts reinforced throughout

Consistent Hashing Caching CAP Theorem Idempotency Sharding / Data Partitioning

Up next

Database & Storage Deep Dive

From a distributed cache to an object store to a global event log — how data is stored, replicated, and retrieved at scale across fundamentally different storage engines.

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