# Software Engineer
**Role:** Software Engineer · **Level:** L7
**Company:** [Patreon](https://scaleengineer.com/companies/patreon)
**Difficulty:** Hard
**Salary:** US$180000 - US$250000
**Experience:** 8 - 15
**Timeline:** ~14 days
The interview process for an L7 Software Engineer at Patreon is designed to assess a candidate's technical expertise, problem-solving abilities, system design skills, and cultural fit. It typically involves multiple rounds, including technical interviews, a system design interview, and behavioral interviews.
Canonical: https://scaleengineer.com/interviews/patreon/l7-software-engineer
---
## Overall evaluation

- Technical Skills
- System Design
- Behavioral and Cultural Fit

## Questions asked

- Design a URL shortener service.
- How would you design a system to handle real-time analytics for millions of creators?
- Describe a time you had a significant disagreement with a colleague. How did you resolve it?
- What are the trade-offs between SQL and NoSQL databases for a platform like Patreon?
- How do you approach performance optimization in a large-scale distributed system?
- Tell me about a time you failed. What did you learn from it?
- Design a rate limiter for an API.
- How would you ensure the reliability and availability of a critical service?
- Describe your experience with mentoring junior engineers.
- What are your thoughts on microservices vs. monolith architectures?

## Preparation tips

### lists

- Review core computer science concepts (data structures, algorithms).
- Practice system design problems, focusing on scalability, availability, and trade-offs.
- Prepare examples for behavioral questions using the STAR method (Situation, Task, Action, Result).
- Research Patreon's products, mission, and engineering culture.
- Understand common distributed systems patterns and technologies.
- Be ready to discuss your past projects in detail, highlighting your contributions and challenges.

### studyPlan

- {"title":"Data Structures and Algorithms","longDescription":"Weeks 1-2: Focus on Data Structures and Algorithms. Review fundamental data structures (arrays, linked lists, trees, graphs, hash maps) and algorithms (sorting, searching, dynamic programming, graph traversal). Practice coding problems on platforms like LeetCode, focusing on medium to hard difficulty.","shortDescription":"Weeks 1-2: DSA fundamentals and practice (LeetCode medium/hard)."}
- {"title":"System Design","longDescription":"Weeks 3-4: Dive into System Design. Study concepts like scalability, availability, consistency, load balancing, caching, databases (SQL vs. NoSQL), message queues, and microservices. Work through common system design interview questions and practice drawing architecture diagrams.","shortDescription":"Weeks 3-4: System Design concepts and practice (scalability, databases, APIs)."}
- {"title":"Behavioral and Leadership","longDescription":"Week 5: Prepare for Behavioral and Leadership questions. Reflect on your career experiences and prepare specific examples using the STAR method for questions related to teamwork, conflict resolution, leadership, mentorship, and handling failure. Understand Patreon's values and how your experiences align.","shortDescription":"Week 5: Behavioral questions (STAR method) and cultural fit."}
- {"title":"Mock Interviews and Review","longDescription":"Week 6: Mock Interviews and Review. Conduct mock interviews with peers or mentors to simulate the interview environment. Review any areas you feel less confident in, and ensure you have clear, concise answers for common questions.","shortDescription":"Week 6: Mock interviews and final review."}

## Location differences

- {"location":"San Francisco","differences":{"tips":["Familiarize yourself with AWS services relevant to large-scale applications.","Be prepared to discuss trade-offs in distributed system design.","Highlight experience with CI/CD pipelines and infrastructure as code."],"interviewFocus":["Emphasis on distributed systems and high-throughput architectures.","Deep dive into cloud-native technologies (AWS, Kubernetes).","Understanding of performance optimization and cost management in a cloud environment."],"commonQuestions":["How would you design a scalable notification system for Patreon?","Discuss a time you had to deal with a complex technical debt. How did you approach it?","Describe a challenging debugging scenario you encountered and how you resolved it."]}}
- {"location":"Remote","differences":{"tips":["Prepare examples demonstrating leadership and mentorship.","Be ready to discuss your experience with data warehousing and ETL processes.","Showcase your ability to contribute to a positive team culture."],"interviewFocus":["Focus on data engineering and analytics pipelines.","Assessing leadership potential and team collaboration skills.","Understanding of best practices for code reviews and testing strategies."],"commonQuestions":["How would you design a real-time analytics dashboard for creator performance?","Tell me about a time you mentored junior engineers. What was your approach?","How do you ensure code quality and maintainability in a large codebase?"]}}

## Round 1: Technical Coding Round 1
**Type:** Data Structures and Algorithms Interview · **Difficulty:** Hard · **Duration:** 60 min
Coding challenge focusing on algorithms and data structures.
This round focuses on your core computer science fundamentals. You will be presented with 1-2 coding problems that require you to implement solutions using appropriate data structures and algorithms. The interviewer will assess your ability to write clean, efficient, and correct code, as well as your approach to problem-solving and debugging.
**Interviewers look for:** Strong grasp of algorithms and data structures.; Ability to translate requirements into working code.; Clear communication of thought process.; Attention to detail and edge cases.
**Evaluation criteria:** Correctness of the solution; Efficiency of the solution (time and space complexity); Code clarity and maintainability; Problem-solving approach; Ability to handle edge cases
**Common rejection reasons:** Inability to articulate thought process clearly.; Lack of fundamental data structure/algorithm knowledge.; Suboptimal or incorrect code implementation.; Poor time management during coding.
## Questions

- Given a binary tree, find its inorder traversal.
- Implement a function to find the k-th largest element in an unsorted array.
- Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

## Preparation tips

- Practice coding problems on platforms like LeetCode, HackerRank, or AlgoExpert.
- Focus on understanding the time and space complexity of your solutions.
- Be prepared to explain your thought process step-by-step.
- Practice writing code on a whiteboard or in a shared editor without an IDE's assistance.

## Round 2: System Design Round
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Design a scalable system for a given problem.
This round assesses your ability to design and architect complex, scalable systems. You will be given an open-ended problem (e.g., design a service like Twitter's feed, a distributed cache, or a notification system) and expected to propose a high-level design, discuss trade-offs, and justify your choices. This includes considerations for databases, APIs, caching, load balancing, and potential bottlenecks.
**Interviewers look for:** Ability to design complex systems from scratch.; Deep understanding of distributed systems concepts.; Pragmatic approach to problem-solving.; Ability to justify design choices.
**Evaluation criteria:** Scalability of the proposed solution; Reliability and fault tolerance; Clarity and completeness of the design; Understanding of trade-offs; Knowledge of relevant technologies and patterns
**Common rejection reasons:** Inability to design a scalable and robust system.; Poor understanding of trade-offs.; Lack of clarity in system architecture.; Failure to consider failure modes and edge cases.
## Questions

- Design a system to shorten URLs like bit.ly.
- Design a distributed rate limiter.
- How would you design a real-time analytics dashboard for creator performance on Patreon?

## Preparation tips

- Study common system design patterns and architectures.
- Practice designing systems like Twitter, Facebook News Feed, Uber, etc.
- Understand concepts like CAP theorem, eventual consistency, and different database types.
- Be prepared to draw diagrams and explain your design clearly.

## Round 3: Behavioral and Managerial Round
**Type:** Behavioral Interview · **Difficulty:** Medium · **Duration:** 45 min
Behavioral questions to assess teamwork, leadership, and cultural fit.
This round focuses on your past experiences, leadership potential, and how you work within a team. You'll be asked behavioral questions designed to understand your approach to various work situations, such as handling challenges, collaborating with others, and demonstrating leadership. The goal is to assess your cultural fit and potential to grow within the company.
**Interviewers look for:** Evidence of collaboration and teamwork.; Ability to handle conflict and difficult situations.; Proactive approach to learning and growth.; Alignment with Patreon's mission and values.
**Evaluation criteria:** Communication skills; Teamwork and collaboration; Problem-solving approach in past projects; Leadership and mentorship potential; Cultural fit with Patreon's values
**Common rejection reasons:** Poor communication or interpersonal skills.; Lack of alignment with company values.; Inability to provide specific examples of past experiences.; Negative attitude or lack of enthusiasm.
## Questions

- Tell me about a time you had to work with a difficult teammate. How did you handle it?
- Describe a project you are particularly proud of and your role in its success.
- 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).
- Think about situations where you demonstrated leadership, teamwork, problem-solving, and conflict resolution.
- Research Patreon's company culture and values.
- Be ready to discuss your career goals and why you are interested in Patreon.

## Round 4: Technical Deep Dive Round
**Type:** Technical Deep Dive / Specialization · **Difficulty:** Hard · **Duration:** 60 min
In-depth technical discussion on specific technologies and challenges.
This round is a more in-depth technical discussion, often focusing on specific areas relevant to the team the candidate is interviewing for. It might involve discussing past projects in detail, exploring specific technical challenges, or delving into advanced concepts related to performance, concurrency, or specific technologies used at Patreon. The interviewer will assess the depth of your technical expertise and your ability to apply it to real-world problems.
**Interviewers look for:** Expertise in specific technologies relevant to the role.; Ability to dive deep into technical details.; Experience with scaling and optimizing systems.; Potential to contribute to the team's technical roadmap.
**Evaluation criteria:** Depth of technical knowledge in relevant domains; Ability to discuss specific technologies and their applications; Problem-solving approach in specialized areas; Alignment with the team's technical challenges
**Common rejection reasons:** Lack of deep technical expertise in specific areas.; Inability to articulate complex technical concepts.; Poor fit with the team's technical stack or methodologies.; Unrealistic salary expectations.
## Questions

- Describe the internals of a garbage collector in a language like Java or Go.
- How would you optimize a slow database query in a high-traffic application?
- Discuss the challenges and solutions for achieving high availability in a distributed system.

## Preparation tips

- Review your resume and be prepared to discuss any technology or project in detail.
- Understand the technical stack and challenges of the team you are interviewing for.
- Prepare to discuss advanced topics like concurrency, distributed systems, performance tuning, and specific programming language features.
- Think about how your past experiences can be applied to Patreon's specific needs.