Top 45 Amazon Interview Questions for SDE [Software Development Engineer]

Landing a job at Amazon as a software development engineer is a coveted accomplishment. Amazon hires thousands of engineers every year across various levels like SDE 1, SDE 2, and more senior roles. The Amazon interview process is quite rigorous and to ace the Amazon interview process, it’s important to prepare the most common questions asked during the interviews. In this blog, we will look at some of the most frequently asked Amazon interview questions for SDE roles for candidates with different levels of experience. These will help you to tackle a variety of questions and perform better to shine in your interviews.

Amazon SDE Interview Process And Timeline

The Amazon SDE interview process is a comprehensive procedure that typically spans four to eight weeks. The following steps outline the process:

1. Resume and Cover Letter Screening:

Your resume is initially screened by recruiters to evaluate if your skills and experience match the requirements for the open position. This is a highly competitive stage, with only about 10% of applicants advancing. 

2. HR Recruiter Email Or Call:

If your resume is selected, a recruiter will contact you to discuss your interests and confirm your qualifications and skills.

3. Online Assessment:

Amazon uses online assessments (OAs) mainly to evaluate interns or new graduates, but sometimes for experienced roles too. You may need to complete up to 3 OAs:

OA1: Debugging

OA2: Coding questions

OA3: Work simulation and logical reasoning

4. Phone Interview:

The next step is one or two technical phone interviews, each 45-60 minutes long. The questions cover a mix of technical knowledge, data structures and algorithms, and behavioral skills. After passing this round, you will be invited for an onsite interview. 

5. Onsite Interviews:

Onsite interviews, either virtual or in-person, consist of four to six one-on-one sessions with team members and hiring managers. A crucial aspect of these interviews involves solving coding problems on a whiteboard, specifically focusing on data structures and algorithms. One or two interviews also cover system design questions. All interviews include behavioral questions as well. The coding difficulty varies based on experience level, with simpler questions for juniors compared to mid-level or senior candidates.

Upon successfully completing these stages, you will be extended an invitation to join Amazon as a Software Development Engineer.

Amazon Interview Questions for SDE Role: 

Here are the top Amazon interview questions for a software development engineer that are asked frequently during Amazon’s rigorous SDE recruitment process. These questions cover topics like coding, system design, and leadership principles.

a. Amazon Interview Questions for SDE Freshers

Amazon’s SDE interview process evaluates your core computer science skills and tests your expertise in data structures, object-oriented design, and other fundamental concepts. Here is a list of commonly asked coding questions at Amazon along with sample solutions to help you prepare for your interview.

Q1. What are dynamic data structures?

Answer: Dynamic data structures can grow or shrink as the program runs. This allows flexible data manipulation. They do not have a fixed memory size and you can update it during runtime. 

Q2. Is there a single best sorting algorithm?

Answer: Though each of the algorithms is best suited for specific data structures, Quicksort is considered one of the fastest and most efficient sorting algorithms. Examples of other popular sorting algorithms include Bubble and Merge.

Q3. What is an array?

Answer: An array is a collection of elements stored contiguously in memory. The elements are all of the same type. Arrays organize data so it can be easily searched or sorted.

Q4. How is a linked list different from an array?

Answer: A linked list stores elements non-contiguously in memory. Each element points to the next, forming a chain-like structure. Arrays store elements contiguously.

Q5. What is LIFO and where is it used?

Answer: LIFO stands for Last In First Out. It is a way of accessing data where the most recently added element is removed first. It is used in stacks. Computers use this method when extracting data from the data buffer or an array.

Q6. What is FIFO?

Answer: FIFO stands for First In First Out. It is a way of accessing data where the oldest added element is removed first. In computing, FIFO is commonly used in memory management, scheduling processes, and managing data in storage or communication buffers.

Q7. How does variable declaration affect memory?

Answer: Variable declaration in programming specifies the type and size of data to be stored, influencing memory allocation. It reserves memory space based on the variable’s data type, impacting the program’s efficiency and storage requirements. Proper declaration ensures efficient memory usage, preventing unnecessary allocation and enhancing overall performance.

Also Read: Amazon Software Developer Interview Questions

Q8. What is recursion and where is it used?

Answer: Recursion is a process where a function calls itself directly or indirectly. This function may not have a base case to avoid infinite recursion. It involves calling the same function within itself leading to a call stack. 

Q9. What is a data structure? Give some examples.

Answer: Data structures are storage formats that organize data to be efficiently stored, accessed, and manipulated. Some common data structures are:

• Arrays: They are sequential storage of elements with a fixed size.
• Trees: These are hierarchical structures with nodes.
• Graphs: They are a collection of nodes and edges.

Q10. What is a stack?

Answer: A stack, adhering to the Last In, First Out (LIFO) principle, is a linear data structure where elements are exclusively accessed from the top downwards. This conceptual framework comprises a collection of alike elements and entails two fundamental operations: push, which adds an element, and pop, which removes the most recently added element.

Q11. What is object-oriented programming?

Answer: Object-oriented programming or OOP is a programming model based on data or objects and not on logic or functions. It provides concepts like objects, classes, and inheritance to structure programs. Some programming languages that use this concept are: 

• OOPS Concepts in C++
• OOPS Concepts in Python 
• OOPs Concepts in Java 

Q12. What is a queue?

Answer: A queue is a linear data structure that follows First In First Out (FIFO). The oldest elements are removed before the newer ones. A queue is a list or collection-type data structure where the new data is added at one end, known as the rear end or the tail of the queue. The data is deleted from the other end, called the front end or the head. 

Q13. What is a binary tree?

Answer: A binary tree is a tree where each node has up to two child nodes – a left and right node. It extends linked lists. It is a non-linear data structure. 

Q14. What is a binary search tree?

Answer: A binary search tree stores data so it can be searched very quickly. Left nodes have lower keys than the parent. Right nodes have equal or higher keys.

Q15. What is a graph in data structures?

Answer: A graph contains nodes connected by ordered pairs called edges or arcs. It is used to connect and store data.

b. Amazon Interview Questions For Senior Software Engineer: Systems Design Interview Questions 

The systems design interview is an important part of Amazon’s SDE recruitment process. Interviewers will evaluate how you design large-scale systems and highlight the strengths and weaknesses of various approaches. This section covers frequently asked Amazon interview questions for a software engineer on system design. 

Q16. How would you design the architecture for a social media application like Twitter?

Answer: Designing the architecture for a social media application like Twitter involves various components to ensure scalability, responsiveness, and reliability. Here’s an overview:

• Clarify Requirements: Seek details on scale, features, and constraints.
• Estimate Storage and Capacity: Evaluate needs based on projected traffic.
• Outline High-Level Components: Identify load-balanced servers, distributed databases, caching layers, and APIs.
• Identify Bottlenecks: Recognize potential issues, e.g., high read volume.
• Design Specific Components: Dive into detailed designs like the home timeline or database schema.
• Validate Design: Ensure the design aligns with availability, scalability, and performance goals.

Q17. How would you design the system architecture and classes for an online multiplayer game like chess? 

Answer: Designing the system architecture and classes for an online multiplayer game like chess involves several key considerations to ensure a scalable, responsive, and enjoyable gaming experience. Here are the steps: 

• Clarify Requirements: Understand game rules, player count, and special features.
• Map Core Classes: Identify the Game, Board, Piece, Spot, and their attributes/methods.
• Define Game Logic: Establish rules for legal moves, checkmate detection, and turn enforcement.
• Communication and Persistence: Determine client-server communication and data persistence.
• Design Specific Components: Dive into user session management and in-progress game saving.
• Validate Requirements: Ensure all gameplay requirements are met.

Q18. How would you design the system for a multi-floor parking garage?

Answer: Designing a system for a multi-floor parking garage involves considering various aspects to ensure efficient parking management and user experience. Here’s an overview:

• Clarify Requirements: Ask questions about capacity needs, payment options, and business goals.
• Core Use Cases: Outline primary use cases: parking, payment, and maintenance.
• Key Classes: Define essential classes: ‘ParkingGarage’, ‘Level’, ‘ParkingSpot’, and ‘Payment’.
• User Flows: Design user flows for activities like ticket issuance, payments, and checking spot availability.
• Component Design: Explore component design for LED signs displaying parking availability, payment processing, and alert generation for exceeding paid time.
• Validation: Ensure functional and non-functional requirements align with the designed solution.

Q19. How would you design a URL-shortening service like Bitly?

Answer: Here are the steps to design a URL-shortening service like Bitly:

• Step 1: Begin by understanding availability and scale requirements.
• Step 2: Evaluate storage needs and bandwidth based on projected traffic.
• Step 3: Outline key components: APIs, database for URL mappings, load balancing, and caching.
• Step 4: Design components for encoding URLs, redirect handling, and customizable short links.
• Step 5: Identify issues like collisions with existing shortcodes and formulate solutions.
• Step 6: Discuss optimizations such as using CDNs for fast redirection.
• Step 7: Ensure the system meets performance and availability goals, especially under high load.

Q20. How would you design a distributed in-memory cache for fast data access?

Answer: Here’s a structured approach to design a distributed in-memory cache for fast data access

• Clarify Functional Requirements: Define requirements, emphasizing O(1) reads and writes, along with availability goals.
• Choose Data Structures: Select suitable data structures, like hashmaps, for efficient data storage.
• Distribution Approaches: Determine distribution methods, such as sharding data across multiple servers.
• Identify Potential Issues: Recognize challenges like hot spots and maximum cache capacity.
• Explore Optimizations: Investigate optimizations, including load balancing, eviction policies, and data replication.
• Check Component Design: Examine component design aspects, such as inter-node communication, fault tolerance, and cache invalidation.
• Verify Targets: Validate performance, scalability, and reliability targets align with the design.

Also Read: Amazon SQL Interview Questions

Q21. How would you design an auto-suggest feature for search?

Answer: Designing an auto-suggest feature for search involves the following key steps:

• Data Structure: Use a trie or an inverted index for efficient storage and retrieval of search terms.
• Query Suggestions: Generate suggestions based on user input, leveraging partial matching and relevance scoring.
• Caching: Utilizecaching mechanisms to store frequently accessed suggestions for faster retrieval.
• User Feedback Loop: Incorporate a user feedback loop to continuously improve and personalize suggestions over time.
• Scalability: Design the system to scale horizontally to handle increasing user queries and data volume.
• User Interface Integration: Seamlessly integrate the auto-suggest feature into the search bar, providing a user-friendly experience.
• Performance Optimization: Optimize for low latency, ensuring quick and responsive suggestions as users type.

Q22. How would you design an API for mobile client apps to access user data?

Answer: Designing an API for mobile client apps to access user data involves the following steps:

• Define API Scope: Clearly outline the scope, usage patterns, and necessary data types for the API.
• Design REST Endpoints: Define REST endpoints and establish the request/response schema for effective communication.
• Authentication and Authorization: Determine robust authentication and authorization mechanisms to control access to the API.
• API Gateway Exploration: Explore the addition of an API gateway to centralize request handling and enhance scalability.
• Component Design: Work on detailed component designs, including encrypting sensitive data, implementing rate-limiting measures, and setting up metrics collection for performance monitoring.
• Identify Risks: Identify potential risks such as SQL injection and develop strategies to mitigate them effectively.
• Validation: Ensure that the API design addresses security concerns, meets availability requirements, and accommodates evolving API needs.

Q23. How would you design the backend system for a messaging platform like WhatsApp?

Answer: Here are the steps to design the backend system for a messaging platform like WhatsApp: 

• Clarify Scale Needs: Define the scale requirements, considering factors such as user base, message volume, and features like group chat.
• Storage Estimates: Calculate storage needs for messages and media, considering both text and multimedia content.
• Define Server Architecture: Identify application servers, databases for messages and users, and caching mechanisms to support efficient data retrieval.
• Explore Component Design: Design components for additional features like push notifications, media downloads, and real-time typing indicators.
• Identify Potential Bottlenecks: Evaluate the system to identify potential bottlenecks, such as overloaded servers or network congestion.
• Optimizations: Discuss optimizations, including the use of Content Delivery Networks (CDNs) for efficient handling of media files.
• Validation: Ensure scalability and high availability for chat functionality, messaging media, and push notifications through thorough validation processes.

Q24. How would you design a cloud file storage and sharing service like Dropbox?

Answer: Here are the steps to design a cloud file storage and sharing service like Dropbox:

• Clarify Requirements: Define usage patterns, security needs, and sharing capabilities for the file storage system.
• Outline Service APIs: Define service APIs for seamless integration, enabling communication with the file storage system.
• Cloud Storage Integration: Explore integration with cloud storage services to leverage scalable and reliable storage solutions.
• Distributed File Systems: Consider the use of distributed file systems for improved performance and fault tolerance.
• Synchronization and Disaster Recovery: Develop strategies for file synchronization across devices and implement disaster recovery mechanisms.
• File Operations: Explore functionalities such as uploading and downloading files, optimizing transfer speeds, handling versioning, and syncing edits.
• CDN Integration: Implement caching mechanisms, utilizing Content Delivery Networks (CDNs) for efficient storage and retrieval of frequently accessed files.
• Identify Risks: Identify potential risks, with a focus on data leaks or security vulnerabilities.
• Verification: Verify that the file storage system meets goals related to storage capacity, transfer speed, availability, and data protection.

Q25. How would you design an e-commerce marketplace like eBay?

Answer: Here are the steps to design an e-commerce marketplace like eBay: 

• Outline Core Flows: Identify and outline core flows, including product search, checkout, and order management.
• Propose Service-Oriented Architecture: Design a service-oriented architecture, detailing components such as app servers, databases, caching, and storage.
• Design Product Catalog and Inventory System: Develop a comprehensive system for managing product catalogs and inventory.
• Explore Additional Features: Consider integrating features like recommendations, promotions, and ad management to enhance the user experience.
• Payment Integration and Order Fulfillment: Divide the process into stages, covering payment integration, order fulfillment, and handling returns.
• Identify Bottlenecks: Identify potential bottlenecks, such as checkout transaction capacity, and devise strategies to mitigate them.
• Discuss Security Risks: Discuss security risks, including vulnerabilities like Cross-Site Scripting (XSS), and implement measures to address them.
• Verification: Verify that the system meets functional, performance, security, and reliability requirements through thorough testing and validation processes.

Q26. How would you design a ride-sharing platform like Uber?

Answer: Here are the steps to  design a ride-sharing platform like Uber:

• Determine Needs and Features: Identify and define the needs and features of the ride-sharing system.
• Outline High-Level Architecture: Develop a high-level architecture encompassing mobile apps, rider/driver profiles, map integration, vehicle tracking, and payment processing.
• Explore Matching and Real-Time Features: Delve into features like matching riders to drivers, real-time location tracking, and dynamic pricing management.
• In-Ride Experiences: Design in-ride experiences such as sharing trip progress and providing digital receipts for users.
• Identify Potential Issues: Identify potential issues, including challenges related to driver churn, and devise strategies for resolution.
• Discuss Optimizations: Discuss optimization strategies, like implementing pooled rides, to enhance efficiency and user experience.
• Verification: Verify that the system meets functional requirements and can scale effectively to accommodate projected growth in user base and service demand.

Q27. Design a caching system for a video streaming service like YouTube.

Answer: Here are the steps to design a caching system for a video streaming service like YouTube:

• Clarify Scale Needs and Performance Goals: Define the scale requirements and performance goals, focusing on cache hit rates and low latency.
• Explore Cache Architecture Options: Discuss options such as building an in-memory cache or distributing a cache across multiple servers to meet performance objectives.
• Design Cache Invalidation Strategy: Develop a strategy for cache invalidation, considering the frequency and methods for refreshing or expiring cached data.
• Define Redundancy Policies: Design redundancy policies to ensure data availability and fault tolerance in case of server failures or data corruption.
• Address Hot Spots: Develop approaches for handling hot spots, where specific data is accessed more frequently, to prevent bottlenecks and optimize performance.
• Optimize for Cache Hit Rate and Lookup Latency: Implement optimizations to maximize the cache hit rate, such as efficient algorithms for cache lookups, and reduce latency in data retrieval.
• Include Availability and Reliability Mechanisms: Incorporate mechanisms to ensure high availability and reliability, including failover strategies and backup systems to minimize downtime.

Q28. Design a social network news feed like Facebook.

Answer: Here are the steps to design a social network news feed like Facebook: 

• Outline Core Content Types: Identify core content types in the feed, including posts, photos, and videos, and define the ranking algorithm for scoring relevancy.
• Architect Backend Pipelines: Design backend pipelines to preprocess and score massive amounts of content efficiently.
• Implement Distributed Data Storage: Set up a distributed data storage system to handle the storage of posts, social graphs, and aggregated timelines.
• Prioritize Engaging Content: Establish a ranking mechanism to prioritize highly engaging content, ensuring that it appears prominently in users’ feeds.
• Ensure Low Latency Delivery: Implement measures to ensure low latency delivery, even when dealing with large-scale data processing and content retrieval.

Also Read: Amazon Coding Interview Questions

Q29. Design a ride scheduling and dispatch system like Lyft.

Answer: Here are the steps to design a ride scheduling and dispatch system like Lyft: 

• Define Needs and Features: Identify key features and user needs for a ride scheduling and dispatch system.
• Architect High-Level System: Design a high-level system architecture with components like mobile apps, driver/rider profiles, mapping, and payment processing.
• Real-Time Matching and Pricing: Implement features for real-time matching of riders and drivers, dynamic pricing, and efficient dispatch algorithms.
• Incorporate User Experience: Focus on in-ride experiences, including trip progress sharing and digital receipts, to enhance user satisfaction.
• Address Potential Issues: Identify and address potential issues like driver churn and explore optimizations for pooled rides.
• Ensure Scalability: Verify that the system meets scalability requirements for projected growth, ensuring reliable service and high performance.

Q30. Can you design an online document collaboration tool like Google Docs?

Answer: Here are the steps to  design an online document collaboration tool like Google Docs:

• User Needs and Features: Identify collaborative document editing needs and features.
• Cloud-Based Architecture: Design a cloud-based architecture for real-time collaboration and storage.
• Real-Time Editing: Implement real-time editing capabilities for multiple users.
• Version Control: Develop a robust version control system for document history.
• User Permissions: Incorporate user permission settings for document access control.
• Optimize User Experience: Focus on optimizing the user experience for seamless collaboration.
• Security Measures: Implement robust security measures to protect user data.
• Scalability: Ensure scalability to accommodate growing user bases and document sizes.

iii. Leadership & Behavioral Interview Questions for Amazon SDE Role

This section provides sample questions and answers on Amazon’s leadership principles. During the interview process, you will be asked situational and behavioral interview questions that aim to evaluate how well your values align with key principles such as customer focus, taking ownership, being innovative, etc. Here are some of the best Amazon behavioral interview questions SDE: 

Q31. Tell me about a time you worked with limited resources. 

Answer: I was working on developing a mobile app on a compressed timeline with a small team of two developers. To deliver on time, we had to focus only on the critical must-have features that we knew would provide core value to users. This required prioritizing the backlog. So, we checked in daily to track progress and reprioritized as needed.

Q32. Describe a situation in which you went above and beyond to meet or surpass a client’s requirements or expectations.

Answer: When developing a dashboard for client reporting, I took the initiative to integrate interactive data visualizations even though the client had not explicitly requested them. This involved learning new data visualization skills on my own time. The enhanced visuals provided much more insightful analytics for end users. The client was very impressed that we exceeded their expectations.

Q33. Tell me about a project with unclear responsibilities.

Answer: During a recent project, our team of five developers was assembled hastily, which resulted in unclear roles and responsibilities and consequently led to confusion among team members regarding accountability. I scheduled a working session with the team to discuss each person’s strengths and interests. Based on that, we clarified roles and responsibilities, which helped in coordination significantly.

Q34. Describe an experience where you broadened an initial focus, turning it into something more extensive. 

Answer: While working with the sales team, I was asked to create an internal sales data portal. However, I saw an opportunity to include more data sources and suggested expanding the portal. To show how this would benefit the organization, I made a presentation for the management and gained support for my idea. The result was a highly impactful platform that provided valuable data insights to the organization.

Q35. Has there been a project where you worked with incomplete information or data?

Answer: We were launching a new consumer product but had incomplete data on customer preferences and pain points. To fill those gaps, I designed a survey and a set of interviews to gather direct insights from people in our target demographic. By proactively seeking this missing information, we were able to develop the right features and messaging to appeal to our audience.

Also Read: Amazon HR Interview Questions

Q36. Tell us about a time you missed a deadline.

Answer: Early in my career, I was managing a large website redesign project that involved complex integrations with backend systems. I underestimated the technical challenges and difficulties of coordinating such a large initiative. As a result, we missed our initial go-live date. Going forward, I learned to build in more buffer time for large complex projects and touch base with engineers daily to catch arising issues early.

Q37. What was the biggest failure of your career? What did you learn from it?

Answer: The biggest failure of my career was leading a product development effort several years ago without getting buy-in from key internal stakeholders early on. Since we did not take their needs into account, our end product solution completely missed the mark once launched internally. I learned a critical lesson – for any large initiative to be successful, you need to engage all key players early and often to understand their needs and get their input.

Q38. Give an example of quickly learning something new for a task.

Answer: I was tasked with analyzing data using a modeling technique with which I was previously unfamiliar. To ensure that I could effectively complete this task, I took the initiative to dedicate several evenings over two weeks to learning this methodology through an online SQL data analytics course. Thanks to this proactive approach, I was able to conduct the specialized analysis required and deliver the completed request within the agreed-upon timeframe.

Q39. Give an example of building trusting work relationships.

Answer: When I joined my current team, I made an effort to build relationships and trust with my teammates. I took time to get to know them personally and understand their working styles. I made sure to deliver consistently on commitments which helped build my reliability. Also, I proactively communicated changes or issues that could have impacted the team’s efficiency. These efforts paid off in strong mutual trust.

Q40. Share a time when you received constructive criticism or negative feedback from your manager. 

Answer: My manager once gave me critical feedback that I was not keeping her sufficiently informed on the status of projects and potential roadblocks. Though difficult to hear, I recognized the validity of the critique. From then on, I made sure to communicate with my manager regularly with project updates or if any issues had arisen. My communication improved dramatically as a result.

Q41. Tell us about resolving a dispute at work.

Answer: In my role as a Software Development Engineer, I came across a dispute within the team regarding the choice of a programming framework for an upcoming project. To resolve the issue, I took the initiative to arrange a team meeting and encouraged everyone to share their viewpoints. In the meeting, we evaluated the advantages and disadvantages of each framework. 

We collectively considered technical requirements, project timelines, and team members’ expertise. After a thorough discussion, we reached a consensus on the most suitable framework. This experience taught me the importance of effective communication and collaboration in resolving workplace disputes and achieving team goals.

Q42. Tell us about a poor decision you made and its impact.

Answer: Early in my career, I made a poor decision in planning timelines for a client project. I was overly optimistic about how quickly we could complete certain complex technical integrations. As a result, the project ended up missing our committed delivery date by over three weeks. This major delay ruined the client’s trust in our team’s ability to execute the project. Due to the delay, the client no longer wanted to continue working with us on future projects. This experience taught me the importance of building contingencies based on a realistic assessment of project risks and uncertainties. I now always get feedback from engineers before committing to timelines. 

Q43. How would you motivate your team?

Answer: I would motivate my team by: 

• Setting clear goals and metrics for success so everyone understands priorities.
• Recognizing achievements and progress creates a sense of purpose.
• Leading by example by working hard and being passionate about our shared mission.

Q44. What approach do you follow to handle challenging situations with customers? Share an instance? 

Answer: I once had a frustrated client who was upset with a delay. I listened calmly, apologized for the issue, and worked to resolve it quickly. In hindsight, I would have communicated more proactively about potential delays.

Q45. How do you prioritize while handling several customers?

Answer:  It can be challenging to provide excellent service to all clients while handling a high volume of customer service requests. To tackle this, I prioritize incoming requests based on their urgency and impact. I focus on resolving issues that will benefit the most customers first. For individual complex issues, I collaborate with my teammates to find the best solution. Clear communication with clients regarding expected resolution timelines is crucial. By balancing quick responses to urgent issues and optimizing solutions for maximum customer benefit, I always strive to provide quality service at scale.

Conclusion:

The interview process at Amazon is quite comprehensive and intensive. Amazon interview questions for the position of SDE typically asses your coding abilities, system designing skills, personality, and leadership skills. The Amazon SDE role is highly competitive. However, by being strategic and meticulous with your preparation and using this guide you can boost your chances of landing your dream job. Are you preparing to interview for the role of software development engineer at Amazon? Also, check out our blog on top Amazon Interview Questions and Answers