# SDE III
**Role:** Software Engineer · **Level:** L
**Company:** [Expedia](https://scaleengineer.com/companies/expedia)
**Difficulty:** Hard
**Salary:** US$150000 - US$200000
**Experience:** 7 - 10
**Timeline:** ~14 days
Expedia's SDE III interview process is designed to assess a candidate's technical expertise, problem-solving abilities, system design skills, and cultural fit for a senior engineering role. The process typically involves multiple rounds, including technical screenings, coding challenges, system design discussions, and behavioral interviews.
Canonical: https://scaleengineer.com/interviews/expedia/l-software-engineer
---
## Overall evaluation

- Technical Skills
- Communication & Collaboration
- Leadership & Impact
- Cultural Fit

## Questions asked

- Given a list of user IDs and their last login timestamps, find all users who logged in within the last 7 days.
- Design a system to handle real-time flight status updates for millions of users.
- How would you implement a rate limiter for an API?
- Describe a time you had to deal with a production issue. What was your approach?
- What are the trade-offs between monolithic and microservices architectures?
- Write a function to find the k-th largest element in an unsorted array.
- How do you ensure data consistency in a distributed system?
- Tell me about a challenging project you led. What was your role and what was the outcome?
- Explain the concept of eventual consistency.
- Design a URL shortening service like bit.ly.

## Preparation tips

### lists

- Review fundamental data structures and algorithms.
- Study system design principles for scalability, reliability, and maintainability.
- Practice coding problems on platforms like LeetCode, HackerRank, or AlgoExpert, focusing on medium to hard difficulty.
- Prepare to discuss your past projects in detail, highlighting your contributions and technical decisions.
- Research Expedia's products, services, and recent engineering challenges.
- Understand common behavioral interview questions and prepare STAR method (Situation, Task, Action, Result) responses.
- Familiarize yourself with cloud computing concepts (AWS, Azure, GCP) and distributed systems.
- Practice explaining your thought process clearly and concisely, especially during coding and system design rounds.

### studyPlan

- {"title":"Data Structures & Algorithms","longDescription":"Weeks 1-2: Focus on core data structures (arrays, linked lists, trees, graphs, hash maps) and algorithms (sorting, searching, dynamic programming, graph traversal). Practice implementing these efficiently and analyze their time/space complexity. Aim for 2-3 problems per day.","shortDescription":"Weeks 1-2: Data Structures & Algorithms fundamentals. Practice 2-3 problems daily."}
- {"title":"System Design","longDescription":"Weeks 3-4: Dive into system design. Study concepts like load balancing, caching, databases (SQL vs. NoSQL), message queues, microservices, and distributed systems. Work through common system design case studies (e.g., designing Twitter, Uber, Netflix).","shortDescription":"Weeks 3-4: System Design principles and case studies."}
- {"title":"Behavioral Preparation","longDescription":"Week 5: Prepare for behavioral interviews. Reflect on your career experiences and identify examples that showcase leadership, teamwork, problem-solving, and handling challenges. Practice articulating these using the STAR method.","shortDescription":"Week 5: Behavioral interview preparation using STAR method."}
- {"title":"Company Research & Mock Interviews","longDescription":"Week 6: Review Expedia-specific technologies and challenges. Read engineering blogs, understand their business model, and prepare questions to ask the interviewer. Do mock interviews to simulate the actual interview environment.","shortDescription":"Week 6: Expedia-specific research and mock interviews."}

## Location differences

- {"location":"Seattle","differences":{"tips":["Research Expedia's recent tech blog posts and engineering challenges.","Prepare to discuss your contributions to open-source projects if applicable.","Be ready to articulate your design choices with clear trade-offs.","Showcase your ability to influence technical direction and mentor others."],"interviewFocus":["Deep understanding of distributed systems and cloud-native architectures.","Experience with large-scale data processing and analytics.","Strong leadership and mentoring capabilities.","Familiarity with Expedia's technology stack and business domain."],"commonQuestions":["Discuss a complex technical challenge you faced and how you overcame it.","How do you approach designing a scalable and reliable system for [specific Expedia product, e.g., flight search]? ","Describe a time you had to mentor junior engineers. What was your approach?","What are your thoughts on the latest trends in cloud computing and how can they be applied at Expedia?"]}}
- {"location":"Chicago","differences":{"tips":["Practice coding problems that involve concurrency and multithreading.","Be prepared to whiteboard system designs, explaining your thought process.","Highlight instances where you've improved team processes or efficiency.","Demonstrate a proactive approach to problem-solving and continuous learning."],"interviewFocus":["Proficiency in data structures and algorithms, with an emphasis on optimization.","Experience with microservices architecture and API design.","Ability to handle ambiguity and drive projects to completion.","Understanding of agile methodologies and CI/CD practices."],"commonQuestions":["How would you design a real-time pricing engine for travel packages?","Explain the CAP theorem and its implications for a distributed booking system.","Describe a situation where you had to disagree with a technical decision. How did you handle it?","What are your strategies for ensuring code quality and maintainability in a large codebase?"]}}
- {"location":"Remote","differences":{"tips":["Prepare examples that demonstrate your impact on business metrics.","Be ready to discuss trade-offs in system design, such as latency vs. consistency.","Showcase your ability to communicate complex technical ideas clearly.","Emphasize your experience in driving innovation and adopting new technologies."],"interviewFocus":["Strong analytical and problem-solving skills.","Experience with machine learning and data science concepts.","Ability to collaborate effectively with cross-functional teams.","Understanding of performance optimization and scalability challenges."],"commonQuestions":["How would you design a recommendation system for personalized travel experiences?","Discuss your experience with A/B testing and experimentation.","Tell me about a time you failed. What did you learn from it?","What are the key considerations when building a fault-tolerant system?"]}}

## Round 1: Coding Interview
**Type:** Technical Phone Screen / Online Assessment · **Difficulty:** Medium · **Duration:** 45 min
Coding challenge to assess problem-solving and coding skills.
This round typically involves a coding challenge, often conducted via a shared online editor. The interviewer will present a problem that requires the candidate to implement a solution using appropriate data structures and algorithms. The focus is on assessing problem-solving skills, coding proficiency, and the ability to think through edge cases and optimize the solution.
**Interviewers look for:** Clean, well-structured, and bug-free code.; Understanding of time and space complexity.; Ability to test the code thoroughly.; Clear communication of the solution.
**Evaluation criteria:** Correctness of the solution.; Efficiency of the solution (time and space complexity).; Code quality and readability.; Ability to explain the approach and trade-offs.
**Common rejection reasons:** Inability to articulate thought process clearly.; Lack of fundamental data structures and algorithms knowledge.; Inefficient or incorrect code implementation.; Poor time management during the coding exercise.
## Questions

- Given a binary tree, find its inorder traversal.
- Implement a function to find the median of a stream of numbers.
- Find the longest substring without repeating characters.

## Preparation tips

- Practice coding on platforms like LeetCode, focusing on medium-difficulty problems.
- Ensure your development environment is set up for quick coding.
- Think out loud and explain your approach before writing code.
- Test your code with various inputs, including edge cases.

## Round 2: System Design
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Design a scalable and reliable system for a given problem.
This round focuses on a candidate's ability to design complex, scalable, and reliable systems. The interviewer will present an open-ended problem (e.g., design a social media feed, a ride-sharing service, or a distributed cache) and expect the candidate to break it down, discuss various components, identify potential issues, and propose solutions. The discussion will cover aspects like data modeling, API design, scalability, and fault tolerance.
**Interviewers look for:** A structured approach to system design.; Knowledge of distributed systems principles (e.g., CAP theorem, consistency models).; Ability to identify bottlenecks and propose solutions.; Consideration of various system components (databases, caches, load balancers, APIs).; Clear communication of design decisions.
**Evaluation criteria:** Scalability of the proposed design.; Reliability and fault tolerance.; Clarity and completeness of the design.; Understanding of trade-offs and justifications for design choices.; Ability to handle system constraints and requirements.
**Common rejection reasons:** Inability to design a scalable and reliable system.; Lack of understanding of distributed systems concepts.; Poorly defined components or unclear trade-offs.; Failure to consider failure scenarios and error handling.
## Questions

- Design a system to shorten URLs like TinyURL.
- Design a news feed system for a platform like Facebook.
- How would you design a distributed key-value store?

## Preparation tips

- Study common system design patterns and architectures.
- Practice designing systems for scale and reliability.
- Be prepared to draw diagrams and explain your design choices.
- Think about potential failure points and how to mitigate them.
- Understand the trade-offs involved in different design decisions.

## Round 3: Behavioral and Managerial Interview
**Type:** Behavioral / Manager Interview · **Difficulty:** Medium · **Duration:** 45 min
Assess behavioral competencies, leadership, and cultural fit.
This round assesses the candidate's behavioral and leadership qualities. The interviewer will ask questions about past experiences, focusing on how the candidate has handled specific situations, worked in teams, demonstrated leadership, and overcome challenges. The goal is to understand the candidate's work style, problem-solving approach in non-technical contexts, and cultural fit within Expedia.
**Interviewers look for:** Examples of leadership and mentorship.; Ability to work effectively in a team.; Problem-solving approach in non-technical situations.; Cultural fit and alignment with company values.; Enthusiasm and passion for the role.
**Evaluation criteria:** Demonstration of leadership and initiative.; Ability to handle conflict and challenges.; Teamwork and collaboration skills.; Alignment with Expedia's culture and values.; Self-awareness and learning from past experiences.
**Common rejection reasons:** Lack of clear examples to support claims.; Inability to articulate impact or ownership.; Poor alignment with company values.; Negative attitude or lack of enthusiasm.
## Questions

- Tell me about a time you had to influence a team to adopt a new technology.
- Describe a situation where you disagreed with your manager. How did you handle it?
- How do you stay updated with new technologies and industry trends?
- Tell me about a time you failed. What did you learn from it?

## Preparation tips

- Prepare specific examples using the STAR method (Situation, Task, Action, Result).
- Reflect on your strengths, weaknesses, and career goals.
- Be ready to discuss your leadership style and experience mentoring others.
- Show enthusiasm for Expedia and the role.

## Round 4: Technical Vision and Leadership
**Type:** Final Round / Executive Interview · **Difficulty:** Hard · **Duration:** 45 min
Assess technical vision, leadership, and overall fit for a senior role.
This final round, often with a more senior leader, aims to assess the candidate's overall fit for a senior role, their technical vision, and their potential to contribute to the broader engineering organization. It may involve a mix of technical discussions, strategic thinking questions, and a final behavioral assessment. The focus is on leadership, impact, and long-term potential.
**Interviewers look for:** A clear vision for technical excellence.; Ability to mentor and guide other engineers.; Experience in driving technical decisions and architecture.; Proactive problem-solving and ownership.; Strong communication and interpersonal skills.
**Evaluation criteria:** Technical vision and strategic thinking.; Ability to lead and mentor technical initiatives.; Deep understanding of software engineering principles.; Alignment with the team's goals and challenges.; Potential for growth and impact within the organization.
**Common rejection reasons:** Lack of alignment with the team's technical direction.; Inability to demonstrate senior-level impact.; Poor communication of technical vision.; Mismatch in expectations regarding role and responsibilities.
## Questions

- What are your thoughts on the future of travel technology and how can Expedia innovate?
- Describe a time you had to make a significant technical decision with incomplete information.
- How would you foster a culture of technical excellence and continuous learning within a team?

## Preparation tips

- Be prepared to discuss your career aspirations and how they align with Expedia's goals.
- Think about how you can contribute to the team's technical strategy.
- Articulate your leadership philosophy and how you mentor engineers.
- Ask insightful questions about the team, technology, and company direction.