Amazon Web Services Software Engineer interview questions & guide 2026

Behavioral & Leadership Principles

• "Tell me about a time you made a mistake. How did you handle it?" (Ownership/Earn Trust)
• "Describe a time you disagreed with a manager's decision. What did you do?" (Have Backbone)
• "Tell me about a time you had to learn a new technology quickly to deliver a project." (Learn and Be Curious)
• "Give an example of a simple solution you created for a complex problem." (Invent and Simplify)
• "Tell me about a time you received critical feedback. How did you react?" (Earn Trust)

Coding & Algorithms

• "Given a matrix of 0s and 1s, find the number of islands." (Graph Traversal)
• "Design a data structure that supports Insert, Delete, and GetRandom in O(1) time." (HashMap + ArrayList)
• "Given a stream of integers, find the median at any point in time." (Heaps)
• "Serialize and deserialize a binary tree." (Tree Traversal)
• "Find the critical connections in a network." (Graph Theory/Tarjan's Algorithm)

System Design

• "Design a system like Amazon's 'People who bought this also bought...' feature."
• "Design a distributed job scheduler."
• "How would you design a system to handle log ingestion from millions of servers?"
• "Design a chat application like WhatsApp or Slack."

Preparation for AWS is distinct because the company places equal weight on technical competency and cultural alignment. You cannot pass by only being a strong coder; you must also demonstrate the specific behaviors that AWS values.

Leadership Principles (LPs) – 2–3 sentences describing: At AWS, the 16 Leadership Principles are not just inspirational wall art; they are the primary rubric for evaluation. You will be assessed on how well your past actions align with principles like Customer Obsession, Ownership, and Dive Deep. You must prepare specific stories using the STAR method (Situation, Task, Action, Result) that demonstrate these traits in action.

System Design and Scalability – 2–3 sentences describing: Because AWS operates at a planetary scale, interviewers expect you to understand how to build distributed systems that are fault-tolerant and highly available. You should be comfortable discussing load balancing, caching strategies, database sharding, and the trade-offs between consistency and availability (CAP theorem).

Coding and Algorithms – 2–3 sentences describing: You will need to demonstrate strong Computer Science fundamentals, particularly in data structures and algorithms. Expect to write syntactically correct code (often in Java, C++, or Python) on a whiteboard or virtual editor, optimizing for time and space complexity.

Operational Excellence – 2–3 sentences describing: Given the "you build it, you run it" culture, you may be asked how you monitor systems, handle outages, and ensure deployment safety. Showing that you understand metrics, alarms, and root cause analysis is a significant advantage.

The interview process at Amazon Web Services is rigorous and standardized, designed to minimize bias and ensure every hire "raises the bar." It typically begins with an Online Assessment (OA) that tests both your coding ability and your work style. The coding portion usually involves two algorithmic problems, while the work style simulation places you in hypothetical scenarios to test your decision-making against the Leadership Principles.

If you pass the OA, you will move to a phone screen (or video screen) with a hiring manager or senior engineer. This is a 45–60 minute session involving one or two coding problems and several behavioral questions focused on LPs. Success here leads to the final "loop"—a full day of interviews (usually 4–5 rounds) comprising a mix of coding, system design, and deep behavioral dives. One of your interviewers will be a "Bar Raiser," a designated interviewer from a different team whose job is to ensure you are better than 50% of the current employees in the role.

The timeline above illustrates the standard progression from application to offer. Note that the "Onsite Interview" stage is the most intensive, requiring stamina for back-to-back sessions. The Bar Raiser round is often the final or penultimate step and holds veto power, so maintain your energy and focus throughout every interaction.

The AWS interview loop is structured to gather data points across specific competencies. Unlike many other companies, Amazon interviewers are assigned specific "competencies" and Leadership Principles to test. You might feel like you are repeating yourself, or that questions are probing the same story from different angles—this is intentional.

Leadership Principles (Behavioral)

This is the most critical non-technical differentiator. You will not be hired if you fail the LP assessment, regardless of your coding skills. Interviewers will ask "Tell me about a time..." questions to extract data on how you handle conflict, ambiguity, and failure.

Be ready to go over:

• Customer Obsession – How you prioritized a customer need over a short-term technical convenience.
• Ownership – Times you stepped outside your defined role to fix a problem or drive a result.
• Bias for Action – Situations where you took a calculated risk to move fast without perfect information.
• Have Backbone; Disagree and Commit – How you respectfully challenged a decision you disagreed with, and how you supported the team once a final decision was made.

Example questions or scenarios:

• "Tell me about a time you had to make a decision with incomplete data."
• "Describe a situation where you missed a deadline. How did you handle it?"
• "Give me an example of a time you went way beyond the scope of the project to deliver for a customer."

Data Structures & Algorithms

You must be able to translate your thoughts into clean, working code. AWS values logical problem solving and code maintainability.

Be ready to go over:

• Core Structures – HashMaps, Arrays, Linked Lists, Trees (Binary Search Trees, Tries), and Graphs.
• Algorithms – BFS/DFS, Sliding Window, Two Pointers, Dynamic Programming (less common but possible), and Recursion.
• Complexity Analysis – You must articulate the Big O time and space complexity of your solution immediately.

Example questions or scenarios:

• "Design an algorithm to find the most frequent keywords in a stream of logs."
• "Implement a Least Recently Used (LRU) cache."
• "Traverse a graph to find the shortest path between two nodes in a network."

System Design

For mid-level and senior roles, this is a make-or-break section. You will be asked to design a system relevant to AWS products.

Be ready to go over:

• Scalability – Horizontal vs. vertical scaling, load balancers, and sharding.
• Database Choice – When to use SQL (RDS, Aurora) vs. NoSQL (DynamoDB) vs. In-memory (ElastiCache).
• Reliability – Replication, failover strategies, and eventual consistency.
• Advanced concepts – Gossip protocols, consistent hashing, and leader election.

Example questions or scenarios:

• "Design a URL shortening service like bit.ly."
• "Design a distributed key-value store like DynamoDB."
• "How would you architect a system to handle millions of requests per second for a flash sale?"

Object-Oriented Design

You may be asked to design a low-level class structure for a specific problem. This tests your ability to write maintainable, extensible code.

Be ready to go over:

• Design Patterns – Singleton, Factory, Strategy, and Observer patterns.
• SOLID Principles – Ensuring your classes are loosely coupled and highly cohesive.

Example questions or scenarios:

• "Design a parking lot system."
• "Design the classes for a Linux file permission system."

As a Software Engineer at AWS, your daily work involves much more than just receiving a ticket and writing code. You are expected to own the "how" of the product. You will translate complex functional requirements—often from Product Managers or external customers—into detailed technical specifications and project plans. You will frequently collaborate with Principal Engineers to ensure your architectural choices align with broader AWS standards for security and reliability.

A significant portion of your role involves operational excellence. You will participate in on-call rotations, where you are responsible for the health of your service. This means you will write and maintain metrics, dashboards, and alarms to detect issues before they impact customers. You will also conduct "Correction of Error" (COE) reviews to analyze root causes of failures and prevent recurrence.

Innovation is a constant expectation. Whether you are on the Neuron team optimizing compilers for machine learning chips, the Redshift team improving query execution engines, or the Connect team building real-time communication platforms, you will be pushing the boundaries of what is possible. You will mentor junior engineers, conduct code reviews to maintain a high quality bar, and drive technical strategy for your specific component or service.

To succeed as a Software Engineer at AWS, you need a solid technical foundation and the ability to operate in a fast-paced, sometimes ambiguous environment.

Technical Skills

• Must-have skills – Proficiency in at least one modern programming language (Java, C++, Python, or C#). Strong command of Computer Science fundamentals including object-oriented design, data structures, and algorithm design. Experience with Linux/Unix environments.
• Nice-to-have skills – Experience with AWS services (EC2, S3, Lambda, DynamoDB). Knowledge of distributed systems design. Familiarity with frontend frameworks (React, Angular) if applying for full-stack roles. Experience with Rust is increasingly valuable in high-performance teams like Aurora and Cryptography.

Experience Level

• Entry-level (SDE I) – Typically requires a Bachelor’s degree in Computer Science or equivalent. Focus is on coding ability and learning capacity.
• Mid-level (SDE II) – Usually requires 3+ years of professional experience. You are expected to be independent, capable of designing small-to-medium systems, and able to mentor interns or new hires.
• Senior (SDE III) – Typically 7+ years of experience. Focus shifts to architecture, team leadership, and driving large-scale technical decisions across multiple teams.

Soft Skills

• Communication – You must be able to articulate technical trade-offs to non-technical stakeholders.
• Ambiguity – You must be comfortable moving forward even when requirements are not fully defined.

Q: How important is the 'Bar Raiser' round? It is critical. The Bar Raiser has veto power over the hiring decision, even if the hiring manager wants to hire you. Their goal is to ensure long-term quality and culture fit. You won't know exactly who they are, so treat every interviewer with equal importance.

Q: Do I need to know AWS services to pass the interview? For general SDE roles, no. You are evaluated on general engineering fundamentals and system design concepts. However, knowing AWS building blocks (like EC2, S3, DynamoDB) helps you articulate your system design solutions more effectively.

Q: How much time should I spend preparing for Leadership Principles? You should spend at least 40-50% of your prep time on LPs. Many strong engineers fail AWS interviews because they focus entirely on coding and neglect to prepare deep, specific stories for the behavioral questions.

Q: What is the preferred programming language for interviews? AWS is language-agnostic in interviews. You can usually choose Java, C++, Python, or C#. Choose the language you are most comfortable with, as you will be expected to write syntactically correct code on a whiteboard or shared editor.

Q: Is the work environment fully remote? Most current job postings for AWS indicate a hybrid model, typically requiring employees to be in the office 3 to 5 days per week. Specifics vary by team and location (e.g., Seattle, Arlington, New York), so clarify this with your recruiter early on.

Use "I" not "We": When answering behavioral questions, interviewers want to know what you specifically contributed. If you constantly say "we did this," the interviewer cannot assess your individual impact. Be specific about your role.

Clarify before coding: In the technical rounds, do not jump straight into coding. Ask questions to clarify constraints (e.g., "Does the input fit in memory?", "Are the logs sorted?"). This demonstrates Customer Obsession and Dive Deep by showing you want to understand the problem fully before solving it.

Data-driven answers: When describing your results in behavioral questions, use numbers. Instead of saying "I improved performance," say "I reduced latency by 200ms, which increased conversion by 5%." AWS is a data-driven company.

Understand the "Why": In system design, don't just throw technologies at the problem (e.g., "I'll use Kafka"). Explain why that technology solves the specific bottleneck in the prompt. Trade-off analysis is key to a Senior SDE level assessment.

Becoming a Software Engineer at Amazon Web Services is a challenging but rewarding journey. You are applying to join a team that sets the standard for the global cloud infrastructure. The interview process is demanding because the work is demanding. However, it is also highly predictable: if you master your Data Structures, System Design, and most importantly, the Leadership Principles, you can succeed.

The salary data above provides a baseline for what you can expect. AWS compensation is heavily weighted towards Restricted Stock Units (RSUs), which vest over time, aligning your success with the company's long-term performance. Note that offers can vary significantly based on location (e.g., Bay Area vs. Seattle vs. Arlington) and the specific level (SDE I, II, or III) you are assessed at during the interview loop.

Focus your preparation on building a "bank" of stories that showcase your ownership and problem-solving skills. Practice coding problems until you can solve them cleanly and efficiently. Approach the interview not as a test, but as a conversation with future colleagues about how to build great software. With the right preparation, you can demonstrate that you are ready to build the future of the cloud. Good luck!