A FAANG software engineer interview has three distinct rounds: data structures and algorithms, system design, and behavioral. Each requires a different preparation approach. This guide gives you a step-by-step roadmap for all three, plus what to do on the day of the interview itself.
Phase 1 — Data Structures & Algorithms (Weeks 1–6)
This is the most time-intensive phase. The goal is pattern recognition, not memorisation.
Arrays, strings, hash maps, two pointers, sliding window. These cover ~40% of real questions.
Trees (BFS/DFS), linked lists, stacks, queues. Every company asks at least two tree problems.
Graphs (DFS/BFS on adjacency list), union-find, topological sort.
Dynamic programming (top-down memoisation, common patterns: knapsack, LCS, intervals).
Target: 150–200 LeetCode problems (mix of Easy/Medium/Hard). Do not just solve — understand why the solution works and what other patterns it relates to.
Phase 2 — System Design (Weeks 5–8)
System design interviews have no single right answer — they are conversations about trade-offs. You will be asked to design systems like URL shorteners, news feeds, ride-sharing backends, and distributed databases.
Master these concepts:
- Scalability — horizontal vs vertical scaling, load balancers, stateless services
- Databases — SQL vs NoSQL, sharding, replication, CAP theorem
- Caching — Redis, CDN, cache invalidation strategies
- Message queues — Kafka, SQS, async processing patterns
- APIs — REST vs gRPC, rate limiting, pagination
Phase 3 — Behavioral (Weeks 7–8)
Every FAANG company (especially Amazon with its Leadership Principles) places heavy weight on behavioral rounds. Prepare 8–10 strong career stories covering: leadership under pressure, conflict resolution, failure and learning, ambiguity, and measurable impact.
Use the STAR method (Situation, Task, Action, Result) for every answer. Quantify results wherever possible — "reduced latency by 40%" beats "made it faster."
What Should You Do on Interview Day?
Preparation gets you 80% of the way. The remaining 20% is performance under pressure — and that is a different skill. Some candidates with deep knowledge blank on problems they have solved dozens of times. A few things that help:
- Think out loud — interviewers want to see your reasoning process, not just the answer
- Clarify before coding — ask about input constraints, edge cases, expected output format
- Start with brute force — then optimize. A working O(n²) solution is better than an incomplete O(n log n) one
- Use Amigo for real-time support — AI streamed answers and a human buddy watching your transcript keep you anchored when you freeze
Your real-time safety net for interview day
Amigo listens during your FAANG interview and streams AI-generated answers as questions are asked. Invisible to screen share. Free to try.
Try Amigo free →Frequently Asked Questions
How long to prepare for a FAANG interview?
8–16 weeks with 1–2 hours of daily practice. More time if you are learning data structures from scratch.
What topics are covered?
Data structures and algorithms, system design, and behavioral questions. All three are mandatory at every FAANG company.
How many LeetCode problems should I do?
150–200 is a common target. Focus on pattern recognition across problem types rather than grinding raw volume.
Is system design important for new grad roles?
Less so than for senior roles, but it still appears. Focus on fundamentals — you will not be expected to design Twitter at L3.
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