# Software Engineer
**Role:** Software Engineer · **Level:** Principal Software Engineer
**Company:** [FactSet](https://scaleengineer.com/companies/factset)
**Difficulty:** Hard
**Salary:** US$170000 - US$220000
**Experience:** 8 - 15
**Timeline:** ~14 days
FactSet is seeking a Principal Software Engineer to join our dynamic team. This role involves designing, developing, and maintaining complex software systems, mentoring junior engineers, and contributing to architectural decisions. The ideal candidate will have a strong background in software development, excellent problem-solving skills, and a passion for building high-quality, scalable solutions.
Canonical: https://scaleengineer.com/interviews/factset/principal-software-engineer-software-engineer
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## Overall evaluation

- Technical Skills
- Leadership and Collaboration
- Problem Solving and Strategic Thinking

## Questions asked

- Describe a complex system you designed or significantly contributed to. What were the key challenges and how did you address them?
- How would you design a system to handle millions of concurrent users?
- Tell me about a time you had to mentor a junior engineer. What was your approach and what was the outcome?
- What are your thoughts on microservices vs. monolithic architectures?
- How do you ensure the security and reliability of the systems you build?
- Describe a situation where you had to make a difficult technical trade-off. What was your reasoning?
- How do you approach code reviews and ensure code quality across a team?
- What are your strategies for managing technical debt?
- Tell me about a time you failed. What did you learn from it?
- How do you stay current with new technologies and industry trends?

## Preparation tips

### lists

- Review core computer science fundamentals, including data structures and algorithms.
- Brush up on system design principles and common architectural patterns.
- Prepare to discuss your past projects in detail, focusing on your contributions and technical challenges.
- Practice explaining complex technical concepts clearly and concisely.
- Research FactSet's products and services to understand our business context.
- 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 Data Structures and Algorithms. Review fundamental data structures (arrays, linked lists, trees, graphs, hash tables) and algorithms (sorting, searching, dynamic programming, graph traversal). Practice solving problems on platforms like LeetCode, HackerRank, or AlgoExpert, focusing on medium to hard difficulty problems. Aim for at least 2-3 problems per day.","shortDescription":"Weeks 1-2: DSA fundamentals. Practice medium/hard problems (2-3/day)."}
- {"title":"System Design","longDescription":"Weeks 3-4: Dive into System Design. Study common system design patterns (load balancing, caching, databases, message queues, microservices). Read resources like 'Designing Data-Intensive Applications' and practice designing scalable systems. Focus on trade-offs and justifications for design choices.","shortDescription":"Weeks 3-4: System Design principles. Study patterns, read books, practice designs."}
- {"title":"Behavioral and Leadership","longDescription":"Week 5: Behavioral and Leadership Preparation. Reflect on your past experiences using the STAR method (Situation, Task, Action, Result). Prepare stories that highlight your leadership, problem-solving, collaboration, and mentoring skills. Consider common behavioral questions related to conflict resolution, failure, and success.","shortDescription":"Week 5: Behavioral prep. Use STAR method for leadership/problem-solving stories."}
- {"title":"Company Research & Mock Interviews","longDescription":"Week 6: Company Research and Mock Interviews. Research FactSet's mission, values, products, and recent news. Conduct mock interviews with peers or mentors to simulate the interview environment and get feedback on your technical and behavioral responses. Refine your answers and practice articulating your thoughts clearly.","shortDescription":"Week 6: Research FactSet. Conduct mock interviews. Refine answers."}

## Location differences

- {"location":"New York","differences":{"tips":["Be prepared to discuss your experience with large-scale systems and distributed architectures.","Highlight instances where you've led technical initiatives or mentored teams.","Demonstrate a deep understanding of software development best practices and design patterns.","Articulate your thought process clearly when discussing complex technical challenges."],"interviewFocus":["System Design and Architecture","Leadership and Mentorship","Problem-Solving at Scale","Technical Strategy and Vision"],"commonQuestions":["Describe a challenging technical problem you solved at scale.","How do you approach designing a distributed system for high availability?","Tell me about a time you had to influence a team to adopt a new technology or approach.","What are your strategies for mentoring and developing junior engineers?","How do you handle technical debt and ensure code quality in a large codebase?"]}}
- {"location":"London","differences":{"tips":["Emphasize your experience with cloud platforms (AWS, Azure, GCP) and containerization (Docker, Kubernetes).","Provide specific examples of how you've improved system performance or scalability.","Showcase your ability to work effectively in a team and influence technical direction.","Be ready to discuss your understanding of modern software development methodologies."],"interviewFocus":["Technical Depth and Breadth","Collaboration and Influence","Performance Optimization","Cloud Technologies"],"commonQuestions":["How do you ensure the performance and scalability of your applications?","Discuss a time you disagreed with a technical decision and how you handled it.","What is your experience with cloud-native technologies and microservices?","How do you balance innovation with maintaining existing systems?","Describe your approach to code reviews and ensuring code quality."]}}
- {"location":"San Francisco","differences":{"tips":["Prepare to discuss your debugging strategies and how you handle production incidents.","Share your insights on future technology trends and how they might impact software development.","Demonstrate your ability to manage projects and prioritize tasks effectively.","Showcase your commitment to continuous learning and professional development."],"interviewFocus":["Problem Solving and Debugging","Architectural Vision","Continuous Learning","Project Management"],"commonQuestions":["How do you approach debugging complex issues in production?","Tell me about a project where you had to make significant architectural changes.","What are your thoughts on the future of software development and emerging technologies?","How do you stay up-to-date with the latest industry trends?","Describe a situation where you had to manage competing priorities."]}}

## Round 1: Technical Coding Round
**Type:** Data Structures and Algorithms Interview · **Difficulty:** Hard · **Duration:** 60 min
Assess fundamental CS knowledge and coding ability through algorithmic problems.
This round focuses on your fundamental computer science knowledge and your ability to translate problems into efficient code. You will be asked to solve one or two algorithmic problems, often involving data structures like arrays, linked lists, trees, graphs, or hash maps. The interviewer will assess your approach to problem-solving, your coding style, and your ability to analyze the time and space complexity of your solutions. Expect to write code in a shared editor or on a whiteboard.
**Interviewers look for:** Strong analytical and problem-solving skills.; Proficiency in coding and implementing solutions efficiently.; Clear communication of thought process.; Understanding of time and space complexity.
**Evaluation criteria:** Problem-solving approach; Algorithmic thinking; Data structure knowledge; Coding proficiency; Ability to explain solutions
**Common rejection reasons:** Lack of depth in core technical areas.; Inability to articulate thought process clearly.; Poor understanding of system design principles.; Difficulty in handling ambiguity or complex problems.; Lack of leadership or mentoring experience.
## Questions

- Given a binary tree, find the lowest common ancestor of two given nodes.
- Implement a function to find the k-th largest element in an unsorted array.
- Design a data structure that supports insert, delete, search, and getRandom in O(1) average time.

## Preparation tips

- Practice coding problems on platforms like LeetCode, HackerRank, or AlgoExpert.
- Focus on understanding the underlying data structures and algorithms.
- Practice explaining your thought process out loud as you solve problems.
- Be prepared to discuss trade-offs between different approaches.

## Round 2: System Design Round
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Assess ability to design scalable and robust software systems.
This round evaluates your ability to design and architect complex software systems. You'll be presented with a high-level problem (e.g., design a URL shortener, a social media feed, or a distributed cache) and asked to propose a solution. The interviewer will probe your design choices, focusing on scalability, reliability, performance, and trade-offs. Be prepared to discuss various components, databases, caching strategies, and communication protocols.
**Interviewers look for:** Ability to design complex, scalable, and reliable systems.; Deep understanding of distributed systems concepts (e.g., consistency, availability, partitioning).; Proficiency in choosing appropriate technologies and architectural patterns.; Ability to articulate design decisions and justify trade-offs.; Consideration of non-functional requirements (e.g., security, maintainability).
**Evaluation criteria:** System design principles; Scalability and performance considerations; Trade-off analysis; Understanding of distributed systems; Clarity of communication
**Common rejection reasons:** Inability to design scalable and robust systems.; Poor understanding of distributed systems concepts.; Lack of clarity in explaining design choices and trade-offs.; Failure to consider edge cases and failure scenarios.; Not demonstrating leadership or architectural vision.
## Questions

- Design a system like Twitter's news feed.
- How would you design a rate limiter for an API?
- Design a distributed key-value store.

## Preparation tips

- Study system design concepts and common architectural patterns.
- Read books like 'Designing Data-Intensive Applications' and 'System Design Interview – An insider's guide'.
- Practice designing various systems and articulating your thought process.
- Be prepared to discuss trade-offs between different design choices.
- Consider non-functional requirements like scalability, availability, and latency.

## Round 3: Managerial Round
**Type:** Behavioral and Managerial Interview · **Difficulty:** Medium · **Duration:** 45 min
Assess behavioral aspects, leadership, and cultural fit.
This round focuses on your behavioral aspects, leadership potential, and cultural fit. The interviewer will ask questions about your past experiences, focusing on how you've handled various situations, such as leading projects, resolving conflicts, working with difficult team members, and dealing with failure. They will also assess your motivation for joining FactSet and your understanding of the role.
**Interviewers look for:** Evidence of leadership and ability to influence others.; Strong communication and interpersonal skills.; Ability to work effectively in a team environment.; Alignment with FactSet's values and culture.; Proactive approach to challenges and learning.
**Evaluation criteria:** Leadership potential; Teamwork and collaboration; Communication skills; Problem-solving approach; Cultural fit
**Common rejection reasons:** Lack of leadership or mentorship experience.; Poor communication or interpersonal skills.; Inability to handle conflict or difficult situations.; Not demonstrating alignment with company values.; Lack of strategic thinking or business acumen.
## Questions

- Tell me about a time you had to lead a team through a challenging project.
- Describe a situation where you disagreed with a colleague or manager. How did you handle it?
- How do you prioritize your work when faced with multiple competing demands?
- What motivates you to do your best work?

## Preparation tips

- Prepare specific examples using the STAR method (Situation, Task, Action, Result).
- Reflect on your leadership experiences and how you've mentored others.
- Think about situations where you've demonstrated teamwork, communication, and problem-solving skills.
- Research FactSet's values and culture and be prepared to discuss how you align with them.
- Prepare thoughtful questions to ask the interviewer.