# L4
**Role:** Software Engineer · **Level:** SDE I
**Company:** [Amazon](https://scaleengineer.com/companies/amazon)
**Difficulty:** Medium to Hard
**Salary:** US$110000 - US$150000
**Experience:** 2 - 5
**Timeline:** ~14 days
The L4 Software Engineer interview at Amazon (SDE I) is a comprehensive assessment designed to evaluate a candidate's technical skills, problem-solving abilities, and cultural fit within Amazon's Leadership Principles. The process typically involves multiple rounds, including technical interviews focusing on data structures, algorithms, and system design, as well as behavioral interviews to gauge alignment with Amazon's values.
Canonical: https://scaleengineer.com/interviews/amazon/sde-i-software-engineer
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## Overall evaluation

- Technical Skills
- Behavioral Aspects (Leadership Principles)

## Questions asked

- Given an array of integers, find the contiguous subarray with the largest sum.
- Design a system to handle millions of concurrent users for a social media platform.
- Explain the difference between concurrency and parallelism.
- Tell me about a time you had to influence a team to adopt a new technology.
- How would you design an API for a ride-sharing service?
- What are the trade-offs when choosing between a monolithic and a microservices architecture?
- Describe a situation where you had to make a difficult decision with incomplete information.
- Implement a function to reverse a linked list.
- How do you approach debugging a complex issue in a distributed system?
- Tell me about a time you took ownership of a project and saw it through to completion.

## Preparation tips

### lists

- Master fundamental data structures (Arrays, Linked Lists, Trees, Graphs, Hash Tables) and algorithms (Sorting, Searching, Dynamic Programming, Greedy).
- Practice coding problems on platforms like LeetCode, HackerRank, and GeeksforGeeks, focusing on medium and hard difficulty.
- Study system design concepts: scalability, availability, consistency, load balancing, caching, databases (SQL vs. NoSQL), message queues, etc.
- Understand Amazon's 16 Leadership Principles and prepare STAR method (Situation, Task, Action, Result) stories for each.
- Review your past projects and be ready to discuss technical challenges, design decisions, and your contributions.
- Practice mock interviews to simulate the interview environment and get feedback.
- Research Amazon's culture and recent news to understand their business and priorities.

### studyPlan

- {"title":"Data Structures and Algorithms Fundamentals","longDescription":"Weeks 1-2: Focus on core data structures (Arrays, Linked Lists, Stacks, Queues, Trees, Hash Maps) and basic algorithms (Sorting, Searching). Practice implementing these from scratch and analyze their time/space complexity. Solve LeetCode Easy and Medium problems related to these topics.","shortDescription":"Weeks 1-2: Data Structures & Basic Algorithms. LeetCode Easy/Medium."}
- {"title":"Advanced Algorithms and Problem Solving","longDescription":"Weeks 3-4: Dive deeper into advanced algorithms like Dynamic Programming, Greedy algorithms, Graph traversals (BFS, DFS), and Tree traversals. Practice more complex LeetCode Medium and Hard problems. Start exploring common coding patterns.","shortDescription":"Weeks 3-4: Advanced Algorithms (DP, Greedy, Graphs). LeetCode Medium/Hard."}
- {"title":"System Design Basics","longDescription":"Weeks 5-6: Begin system design preparation. Study concepts like scalability, load balancing, caching, databases (SQL vs. NoSQL), APIs, microservices, and distributed systems. Read system design case studies and practice designing common systems (e.g., Twitter feed, URL shortener).","shortDescription":"Weeks 5-6: System Design Fundamentals. Scalability, Caching, Databases."}
- {"title":"Behavioral Preparation (Leadership Principles)","longDescription":"Weeks 7-8: Focus on behavioral preparation. Understand each of Amazon's 16 Leadership Principles. Prepare 2-3 detailed STAR method stories for each principle, drawing from your professional experience. Practice articulating these stories clearly and concisely.","shortDescription":"Weeks 7-8: Behavioral Preparation. STAR Method for Leadership Principles."}
- {"title":"Integration and Practice","longDescription":"Weeks 9-10: Integrate technical and behavioral preparation. Practice mock interviews covering both coding and system design. Refine your system design explanations and behavioral stories. Review weak areas identified during practice.","shortDescription":"Weeks 9-10: Mock Interviews & Refinement. Coding, System Design, Behavioral."}

## Location differences

- {"location":"Seattle, USA","differences":{"tips":["For Seattle/US-based interviews, expect a strong emphasis on system design and distributed systems concepts.","Be prepared to discuss your past projects in detail, highlighting your contributions and the impact.","Practice explaining complex technical concepts clearly and concisely."],"interviewFocus":["System Design: Emphasis on scalability, reliability, and trade-offs.","Coding: Focus on clean, efficient, and well-tested code.","Behavioral: Deep dive into Leadership Principles, especially Ownership, Customer Obsession, and Bias for Action."],"commonQuestions":["How would you design a URL shortener?","Explain the difference between a process and a thread.","Describe a time you had to deal with ambiguity.","Tell me about a challenging technical problem you solved."]}}
- {"location":"Hyderabad, India","differences":{"tips":["For international locations like Hyderabad or London, be ready for a rigorous coding assessment, often involving whiteboard coding or shared editor sessions.","Familiarize yourself with common coding patterns and problem-solving approaches.","Prepare specific examples that demonstrate your problem-solving skills and ability to work in a team."],"interviewFocus":["Coding: Strong focus on algorithms and data structures, with an emphasis on time and space complexity.","Behavioral: Assessment of collaboration, learning agility, and delivering results.","System Design: Evaluation of architectural choices and their justifications."],"commonQuestions":["Design a system for real-time notifications.","What are the trade-offs between SQL and NoSQL databases?","Describe a situation where you failed and what you learned.","How do you handle conflicting priorities?"]}}
- {"location":"London, UK","differences":{"tips":["For European locations, expect a blend of technical depth and practical application of concepts.","Be prepared to discuss your experience with cloud technologies (AWS is a plus).","Showcase your ability to think critically and articulate your thought process."],"interviewFocus":["System Design: Focus on distributed systems, concurrency, and fault tolerance.","Behavioral: Assessment of customer obsession, invent and simplify, and dive deep.","Coding: Evaluation of problem-solving and coding proficiency."],"commonQuestions":["How would you design a distributed cache?","Explain the CAP theorem.","Tell me about a time you disagreed with a decision.","How do you ensure the quality of your code?"]}}

## Round 1: Coding Round 1
**Type:** Data Structures and Algorithms Interview · **Difficulty:** Medium · **Duration:** 45 min
Coding problems focusing on data structures and algorithms.
This round focuses on assessing your core programming skills. You will be asked to solve one or two coding problems, typically involving data structures and algorithms. The interviewer will evaluate your ability to write clean, efficient, and correct code, as well as your problem-solving approach and communication skills. Expect to write code in a shared editor or on a whiteboard.
**Interviewers look for:** A candidate who can translate a problem into a working, efficient code.; Someone who can articulate their thought process clearly.; Ability to identify and fix bugs.; Understanding of asymptotic analysis.
**Evaluation criteria:** Correctness of the solution; Efficiency (Time and Space Complexity); Code clarity and readability; Problem-solving approach; Ability to handle edge cases
**Common rejection reasons:** Inability to solve coding problems efficiently.; Poor understanding of fundamental data structures and algorithms.; Lack of clarity in explaining thought process.; Not meeting the bar for coding quality (e.g., bugs, inefficient solutions).
## Questions

- Given a binary tree, find its inorder traversal.
- Implement a function to find the kth smallest element in an unsorted array.

## Preparation tips

- Practice coding problems on platforms like LeetCode, focusing on common data structures and algorithms.
- Be prepared to explain your approach before coding.
- Think about edge cases and test your code thoroughly.
- Discuss time and space complexity of your solution.

## Round 2: System Design Round
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Design of large-scale distributed systems.
This round evaluates your ability to design large-scale, distributed systems. You'll be presented with a high-level problem (e.g., design Twitter, design a URL shortener) and expected to break it down into components, discuss trade-offs, and justify your design choices. Focus on scalability, availability, and maintainability.
**Interviewers look for:** A candidate who can design complex systems from scratch.; Someone who understands distributed systems principles.; Ability to identify potential bottlenecks and propose solutions.; Strong analytical and critical thinking skills.
**Evaluation criteria:** Scalability of the design; Reliability and fault tolerance; Trade-off analysis (e.g., consistency vs. availability); Understanding of system components (databases, caches, load balancers); Clarity of explanation and justification of design choices
**Common rejection reasons:** Inability to design scalable and reliable systems.; Lack of understanding of distributed systems concepts.; Poor trade-off analysis.; Not considering failure scenarios or bottlenecks.
## Questions

- Design a distributed caching system.
- How would you design a rate limiter for an API?

## Preparation tips

- Study system design concepts thoroughly.
- Practice designing common systems.
- Be prepared to discuss trade-offs and justify your decisions.
- Consider different components like databases, caches, load balancers, and message queues.

## Round 3: Behavioral Round
**Type:** Behavioral Interview · **Difficulty:** Medium · **Duration:** 45 min
Behavioral questions based on Amazon's Leadership Principles.
This round focuses on your behavioral fit with Amazon's culture, assessed through its 16 Leadership Principles. You'll be asked questions about your past experiences, and you should answer using the STAR method (Situation, Task, Action, Result). The interviewer wants to understand how you've demonstrated principles like Customer Obsession, Ownership, Bias for Action, and Learn and Be Curious.
**Interviewers look for:** Candidates who embody Amazon's Leadership Principles.; Individuals who can provide specific, impactful examples from their past.; People who are self-aware and can learn from their experiences.; Strong communicators who can articulate their contributions.
**Evaluation criteria:** Alignment with Amazon's Leadership Principles; Quality and relevance of STAR method examples; Self-awareness and reflection; Communication and storytelling skills; Demonstration of impact and ownership
**Common rejection reasons:** Lack of specific examples demonstrating leadership principles.; Inability to articulate experiences clearly using the STAR method.; Not demonstrating ownership, customer obsession, or bias for action.; Poor self-awareness or inability to reflect on past experiences.
## Questions

- Tell me about a time you had to make a difficult decision. What was the outcome?
- Describe a situation where you went above and beyond for a customer.

## Preparation tips

- Understand all 16 Leadership Principles.
- Prepare specific examples using the STAR method for each principle.
- Be honest and authentic in your responses.
- Focus on your contributions and the impact you made.

## Round 4: Hiring Manager Round
**Type:** Hiring Manager Round · **Difficulty:** Medium · **Duration:** 30 min
Final assessment with the hiring manager.
This is typically the final round, often with the hiring manager. It serves as a final assessment of your overall fit for the team and role. The manager will review your performance in previous rounds, ask further behavioral questions, and discuss your career aspirations. This is also your opportunity to ask questions about the team, role, and company culture.
**Interviewers look for:** A well-rounded candidate who meets the bar across all dimensions.; Someone who is excited about the role and Amazon.; A candidate who asks thoughtful questions.; Confirmation of the candidate's strengths and potential areas for development.
**Evaluation criteria:** Overall technical competence; Cultural fit and alignment with Leadership Principles; Motivation and career aspirations; Candidate's questions and engagement
**Common rejection reasons:** Not meeting the technical bar across multiple rounds.; Poor cultural fit.; Lack of enthusiasm or engagement.; Inability to articulate career goals or alignment with the role.
## Questions

- Why are you interested in this role at Amazon?
- What are your strengths and weaknesses?

## Preparation tips

- Be prepared to summarize your strengths and why you are a good fit.
- Have thoughtful questions ready for the hiring manager.
- Reiterate your enthusiasm for the role and Amazon.