# Software Engineer
**Role:** Software Engineer · **Level:** L4
**Company:** [Twitch](https://scaleengineer.com/companies/twitch)
**Difficulty:** Medium to Hard
**Salary:** US$130000 - US$180000
**Experience:** 3 - 7
**Timeline:** ~14 days
This interview process is for a Software Engineer (L4) position at Twitch. It is designed to assess a candidate's technical skills, problem-solving abilities, and cultural fit within the company.
Canonical: https://scaleengineer.com/interviews/twitch/l4-software-engineer
---
## Overall evaluation

- Technical Skills
- Communication
- Teamwork & Culture Fit

## Questions asked

- Design a system to recommend videos to users on Twitch.
- How would you handle a sudden surge in live stream viewers?
- Write a function to find the k-th largest element in an unsorted array.
- Describe a time you disagreed with a technical decision and how you handled it.
- What are the challenges of building a real-time chat system for millions of users?
- Explain the concept of eventual consistency.
- How do you approach testing your code?
- Tell me about a time you failed and what you learned from it.

## Preparation tips

### lists

- Review fundamental data structures and algorithms.
- Practice coding problems on platforms like LeetCode, HackerRank, or Coderbyte.
- Study system design principles and common architectural patterns.
- Understand concurrency, multithreading, and distributed systems concepts.
- Prepare to discuss your past projects and experiences in detail.
- Research Twitch's mission, values, and products.
- Practice behavioral questions using the STAR method (Situation, Task, Action, Result).
- Prepare questions to ask the interviewers about the role, team, and company culture.

### studyPlan

- {"title":"Data Structures and 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 in your preferred language and analyze their time and space complexity.","shortDescription":"Weeks 1-2: Data Structures & Algorithms fundamentals. Practice coding."}
- {"title":"System Design","longDescription":"Weeks 3-4: Dive into system design concepts. Study topics like scalability, availability, reliability, load balancing, caching, databases (SQL vs. NoSQL), message queues, and microservices. Practice designing common systems like a URL shortener, a Twitter feed, or a chat application.","shortDescription":"Weeks 3-4: System Design principles and practice."}
- {"title":"Behavioral Preparation","longDescription":"Week 5: Prepare for behavioral questions. Reflect on your past experiences and identify examples that demonstrate leadership, teamwork, problem-solving, and handling challenges. Use the STAR method to structure your answers.","shortDescription":"Week 5: Behavioral questions preparation (STAR method)."}
- {"title":"Technology & Questions","longDescription":"Week 6: Review specific technologies relevant to Twitch, such as cloud computing (AWS), containerization (Docker, Kubernetes), and potentially front-end or back-end frameworks depending on the specific team. Also, prepare insightful questions to ask the interviewers.","shortDescription":"Week 6: Technology review and question preparation."}

## Location differences

- {"location":"San Francisco, USA","differences":{"tips":["Familiarize yourself with Twitch's core products and services.","Prepare to discuss specific examples of large-scale systems you've worked on.","Be ready to whiteboard system designs and discuss trade-offs.","Showcase your understanding of asynchronous programming and concurrency.","Highlight any experience with video streaming technologies or protocols."],"interviewFocus":["Deep dive into distributed systems design relevant to live streaming.","Emphasis on scalability and performance optimization for high-traffic applications.","Understanding of real-time data processing and event-driven architectures.","Experience with microservices and containerization technologies."],"commonQuestions":["How would you design a real-time notification system for Twitch?","Discuss a challenging debugging scenario you faced and how you resolved it.","Explain the trade-offs between SQL and NoSQL databases for a large-scale streaming platform.","How do you ensure code quality and maintainability in a fast-paced environment?","Describe your experience with cloud platforms like AWS, Azure, or GCP."]}}
- {"location":"Remote","differences":{"tips":["Be prepared to discuss your contributions to specific features or products.","Highlight your ability to work effectively in a team environment.","Showcase your passion for building engaging user experiences.","Research Twitch's front-end technologies and frameworks.","Practice explaining complex technical concepts clearly and concisely."],"interviewFocus":["Focus on front-end development skills and user experience.","Assessment of collaboration and teamwork abilities.","Understanding of software development lifecycle and best practices.","Problem-solving skills applied to user-facing features."],"commonQuestions":["How would you optimize the performance of a video player component?","Describe a time you had to mentor junior engineers.","What are your thoughts on agile development methodologies?","How do you handle conflicting priorities and deadlines?","Tell me about a project where you had to collaborate with cross-functional teams."]}}

## Round 1: Coding Challenge
**Type:** Technical Interview - Coding · **Difficulty:** Medium · **Duration:** 45 min
Assess coding skills with data structures and algorithms problems.
This round focuses on your fundamental programming skills. You will be asked to solve coding problems that test your knowledge of data structures and algorithms. The interviewer will assess your ability to write clean, efficient, and correct code, as well as your problem-solving approach and communication skills.
**Interviewers look for:** Clean, efficient, and correct code.; Clear explanation of the thought process.; Ability to identify and discuss time/space complexity.; Willingness to consider edge cases and test thoroughly.
**Evaluation criteria:** Problem-solving approach; Coding proficiency; Understanding of data structures and algorithms; Ability to explain code and logic
**Common rejection reasons:** Inability to articulate thought process clearly.; Lack of fundamental data structures and algorithms knowledge.; Poor coding practices or syntax errors.; Inability to optimize solutions for time and space complexity.
## Questions

- Given a binary tree, invert the tree.
- Find the first non-repeating character in a string.
- Implement a Least Recently Used (LRU) cache.

## Preparation tips

- Practice coding problems on platforms like LeetCode.
- Be comfortable explaining your code and thought process.
- Review common data structures and algorithms.
- Practice whiteboarding or using an online editor.

## Round 2: System Design
**Type:** Technical Interview - System Design · **Difficulty:** Hard · **Duration:** 60 min
Assess system design skills for scalable and distributed applications.
This round evaluates your ability to design complex, scalable, and reliable systems. You will be presented with a high-level problem and asked to design a system to solve it. The focus is on your architectural thinking, understanding of distributed systems, and ability to make informed trade-offs.
**Interviewers look for:** Ability to design scalable and reliable systems.; Understanding of trade-offs between different design choices.; Consideration of various components like databases, caching, load balancers.; Ability to communicate complex ideas clearly.
**Evaluation criteria:** System design approach; Scalability and performance considerations; Trade-off analysis; Understanding of distributed systems; Clarity of communication
**Common rejection reasons:** Lack of understanding of system design principles.; Inability to handle scale and performance considerations.; Poor trade-off analysis.; Not considering edge cases or failure scenarios.
## Questions

- Design a system to handle real-time chat for millions of users.
- Design a URL shortening service like bit.ly.
- Design a news feed system for a social media platform.

## Preparation tips

- Study system design concepts (scalability, availability, databases, caching, etc.).
- Practice designing common systems (e.g., Twitter feed, URL shortener).
- Be prepared to discuss trade-offs and justify your design choices.
- Understand how to handle high traffic and large amounts of data.

## Round 3: Hiring Manager Discussion
**Type:** Behavioral Interview / Hiring Manager Interview · **Difficulty:** Medium · **Duration:** 45 min
Assess cultural fit, motivation, and past experiences with the hiring manager.
This round is conducted by the hiring manager to assess your overall fit with the team and company culture. They will delve into your past experiences, motivations, and career goals. You'll also have the opportunity to ask questions about the team, projects, and work environment.
**Interviewers look for:** Enthusiasm for Twitch and the role.; Ability to articulate past experiences clearly.; Good communication and interpersonal skills.; Alignment with Twitch's values.; Potential for growth within the company.
**Evaluation criteria:** Communication skills; Teamwork and collaboration; Problem-solving approach in past projects; Cultural fit; Motivation and interest in Twitch
**Common rejection reasons:** Poor communication skills.; Lack of enthusiasm or interest in the role/company.; Inability to provide specific examples of past experiences.; Not a good cultural fit.; Unrealistic salary expectations.
## Questions

- Tell me about a challenging project you worked on and how you overcame obstacles.
- Why are you interested in working at Twitch?
- How do you handle constructive criticism?
- Describe a time you had to work with a difficult team member.

## Preparation tips

- Research Twitch's company culture and values.
- Prepare to discuss your career goals and why you're interested in this role.
- Have specific examples ready to illustrate your skills and experiences.
- Prepare thoughtful questions to ask the hiring manager.