Amazon Backend Engineer Interview Questions (2026)

1. 1Online Assessment (SDE OA)60 minMedium

   Two timed coding problems plus a workplace-simulation and logic section; the main gate for freshers and India volume hiring.

2. 2Phone screen45 minMedium

   One coding problem plus 1-2 Leadership Principle STAR questions with an SDE.

3. 3Coding loop round60 minMedium

   DSA problem to working code, followed by assigned-LP behavioral questions in STAR format.

4. 4System design loop round60 minHard

   Design an Amazon-scale service with capacity math, plus LPs; low-level/OOD design substitutes for junior candidates.

5. 5Hiring Manager round45 minMedium

   Team fit, project deep dives, and Deliver Results/Bias for Action stories with the manager you would report to.

6. 6Bar Raiser60 minHard

   An interviewer from outside the team stress-tests LP stories and overall bar with the hardest cross-examination of the loop; holds veto.

1. Q1

   Design with ownership boundaries: Design a reusable API client for Alexa with auth refresh and request signing

   MediumLow Level DesignAPI client with auth

   How to answer: Separate HttpClient, AuthProvider, TokenStore, RequestSigner, RetryPolicy, and Serializer; refresh tokens safely and avoid logging secrets. Make ownership, idempotency, and failure modes explicit.

2. Q2

   Ask clarifying questions first; then answer this: Design an API gateway for AWS Lambda backend services

   HardHigh Level DesignAPI gateway

   How to answer: Handle auth, routing, rate limits, request validation, retries/timeouts, observability, and versioning. Keep business logic out of the gateway. Include customer impact, operational metrics, and failure handling.

3. Q3

   Write production-quality, testable code to solve this: Code a mapper from a raw Delivery API response to a stable internal model

   MediumCodingAPI response mapper

   How to answer: Validate required fields, provide defaults for optional fields, isolate external schema changes, and test unknown fields and backward compatibility. Add boundary tests and robust error handling.

4. Q4

   Write production-quality, testable code to solve this: Infer character order from sorted Fulfillment labels in an unknown alphabet

   MediumDSAAlien dictionary

   How to answer: Build precedence edges from first differing characters, then topologically sort. O(total characters); detect invalid prefixes and cycles. Add boundary tests and robust error handling.

5. Q5

   Using STAR and Amazon Leadership Principles, answer this: Tell me about a time you had to deliver a Prime Video project with ambiguous requirements

   SeniorBehavioralAmbiguity

   How to answer: Use STAR: clarify the ambiguity, list options, align stakeholders, deliver an MVP, quantify outcome, and mention what you changed after learning. Name the LP implicitly through actions; include metrics and ownership.

6. Q6

   Write production-quality, testable code to solve this: Write code to call multiple Kindle services concurrently and return partial results safely

   HardCodingAsync fanout

   How to answer: Use async tasks/futures with per-call timeouts, collect successes and errors separately, limit concurrency, and preserve result ordering if required. Add boundary tests and robust error handling.

7. Q7

   Design with ownership boundaries: Design a low-level audit logger for Prime Video administrative actions

   HardLow Level DesignAudit log component

   How to answer: Model AuditEvent, Actor, Target, Metadata, Sink, and Redactor; ensure append-only semantics and safe handling of PII. Make ownership, idempotency, and failure modes explicit.

8. Q8

   Write production-quality, testable code to solve this: Generate all valid configurations for a small Alexa rule set with constraints

   HardDSABacktracking combinations

   How to answer: Use DFS/backtracking, pruning invalid partial states early. Complexity is exponential; explain pruning and output-size limits. Add boundary tests and robust error handling.

9. Q9

   Write production-quality, testable code to solve this: Validate nested delimiters in a Prime Video expression language

   MediumDSABalanced parentheses

   How to answer: Use a stack of opening delimiters and match each closing delimiter. O(n), O(n); reject mismatches and leftover openings. Add boundary tests and robust error handling.

10. Q10

    Using STAR and Amazon Leadership Principles, answer this: Give an example of balancing ship speed and engineering quality for Recommendations

    MediumBehavioralBalancing speed and quality

    How to answer: State deadline and risks, define acceptable quality bar, ship safe slice, add follow-up debt plan, and measure post-launch outcomes. Name the LP implicitly through actions; include metrics and ownership.

11. Q11

    Using STAR and Amazon Leadership Principles, answer this: Tell me about a time you moved quickly on Fulfillment despite incomplete information

    SeniorBehavioralBias for action

    How to answer: Show reversible vs irreversible decision framing, minimum safe data gathered, fast execution, and how you monitored/adjusted after launch. Name the LP implicitly through actions; include metrics and ownership.

12. Q12

    Write production-quality, testable code to solve this: Find the missing ID in a Alexa sequence containing 0..n except one value

    MediumDSABit manipulation missing number

    How to answer: XOR all indexes and values or use arithmetic sum with overflow caution. O(n), O(1); XOR is safer for large integers. Add boundary tests and robust error handling.

13. Q13

    Ask clarifying questions first; then answer this: Design CDN and origin protection for Delivery static assets

    HardHigh Level DesignCDN origin shielding

    How to answer: Use multi-tier caching, signed URLs, cache keys, origin shield, purge pipeline, health checks, and logs for cache hit-rate analysis. Include customer impact, operational metrics, and failure handling.

14. Q14

    For Amazon's payments reconciliation flow, write production-quality backend code to build an LRU cache with TTL and hit/miss metrics while meeting zero-downtime deployment. Describe the main function or class interface, the core data structures, and the edge cases you would test

    MediumCodingCaching

    How to answer: A strong answer proposes a small, testable interface and uses hash map plus doubly linked list or ordered dictionary with lazy expiry. It handles retries, invalid input, timeouts, and cleanup explicitly, and states O(1) expected get/put.

15. Q15

    For Amazon's fulfillment routing flow, write production-quality backend code to implement stale-while-revalidate with request coalescing while meeting limited memory per worker. Describe the main function or class interface, the core data structures, and the edge cases you would test

    MediumCodingCaching

    How to answer: A strong answer proposes a small, testable interface and uses serve fresh or bounded-stale values and allow one refresh per key. It handles retries, invalid input, timeouts, and cleanup explicitly, and states O(1) cache lookup with bounded refresh fanout.

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Prepare 8-12 STAR stories mapped to Leadership Principles; expect a Bar Raiser; quantify impact

Indicative Backend Engineer pay in India: ~₹10–45 LPA (role-level range, not a Amazon-specific figure).

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