23andMe Software Engineer Interview Questions + Guide in 2025

23andMe is a leading consumer genetics and research company dedicated to helping individuals access and understand their genetic information for better health and personal insights.

As a Software Engineer at 23andMe, you will be integral to designing, developing, and maintaining scalable services that are pivotal for both external customers and internal teams. You will take ownership of software delivery, contributing to the development of applications that enhance the company's marketing, e-commerce, sales, and finance capabilities. Key responsibilities include collaborating with product and design teams to align technical solutions with strategic goals, developing secure and high-quality code, and participating in code reviews to promote excellence within the team. A strong foundation in programming languages such as Python or JavaScript, coupled with experience in cloud-based applications and a collaborative mindset, will position you as a valuable asset in this innovative environment.

This guide will equip you with insights and specific areas of focus to help you prepare effectively for your interview, ultimately increasing your chances of successfully securing a position at 23andMe.

The interview process for a Software Engineer at 23andMe is structured to assess both technical skills and cultural fit within the team. It typically consists of several stages, each designed to evaluate different aspects of a candidate's qualifications and compatibility with the company's values.

1. Initial Phone Screen

The process begins with an initial phone screen, usually conducted by a recruiter or the hiring manager. This conversation focuses on your background, interest in the company, and relevant projects you've worked on. It serves as an opportunity for the interviewer to gauge your communication skills and understand your motivations for applying to 23andMe.

2. Technical Phone Interview

If you successfully pass the initial screen, you will be invited to a technical phone interview. This stage involves solving coding problems and answering technical questions related to data structures, algorithms, and possibly system design. Expect to demonstrate your problem-solving abilities and coding proficiency, often using a collaborative coding platform.

3. Coding Challenge

Following the technical phone interview, candidates may be required to complete a coding challenge. This assignment typically involves building a small application or solving a specific problem using programming languages relevant to the role, such as Python or JavaScript. The challenge is designed to assess your coding skills, creativity, and ability to deliver high-quality code.

4. Onsite Interview

Candidates who perform well in the previous stages are invited for an onsite interview. This comprehensive session usually consists of multiple rounds, including one-on-one interviews with various team members. Expect a mix of technical questions, system design discussions, and behavioral interviews. The onsite experience is often collaborative, allowing candidates to engage with potential colleagues and demonstrate their teamwork skills.

5. Final Discussions

After the onsite interviews, there may be a final discussion with the hiring manager or a senior leader. This conversation often focuses on your fit within the team and the company culture, as well as any remaining questions you may have about the role or the organization.

Candidates can expect to receive feedback and updates on their application status after the interview process concludes, although communication may vary in responsiveness.

As you prepare for your interview, it's essential to be ready for the specific technical questions that may arise during the process.

Here are some tips to help you excel in your interview.

Understand the Company Culture

23andMe values collaboration, innovation, and a strong sense of purpose. Familiarize yourself with their mission to help people access and benefit from genetic information. During the interview, express your enthusiasm for their work and how your values align with theirs. Highlight any experiences that demonstrate your commitment to teamwork and your ability to contribute to a mission-driven environment.

Prepare for Technical Challenges

Expect a range of technical questions that may include algorithms, data structures, and system design. Review common coding problems, particularly those that are relevant to the technologies used at 23andMe, such as Python, AWS, and web security practices. Practice coding on a whiteboard or in a collaborative environment, as many interviewers appreciate seeing your thought process in real-time.

Showcase Your Problem-Solving Skills

Be ready to discuss specific technical challenges you've faced in previous roles. Use the STAR (Situation, Task, Action, Result) method to structure your responses. This will help you articulate your thought process and the impact of your solutions. Given the emphasis on mentorship and collaboration at 23andMe, also be prepared to discuss how you've supported the growth of your peers.

Communicate Clearly and Effectively

During the interview, focus on clear communication. Interviewers appreciate candidates who can explain their thought processes and decisions. If you encounter a challenging question, don’t hesitate to verbalize your reasoning. This not only shows your analytical skills but also allows interviewers to guide you if you get stuck.

Be Ready for Behavioral Questions

Expect questions that assess your fit within the team and company culture. Prepare to discuss your experiences working in collaborative settings, how you handle conflict, and your approach to mentorship. Highlight instances where you contributed to a positive team dynamic or helped others succeed.

Follow Up Professionally

After your interview, send a thank-you email to express your appreciation for the opportunity to interview. Mention specific topics discussed during the interview to reinforce your interest in the role and the company. This not only shows professionalism but also keeps you top of mind as they make their decision.

Stay Positive and Resilient

While some candidates have reported challenges with communication during the interview process, maintaining a positive attitude is crucial. If you encounter any setbacks or delays, remain patient and professional. Your resilience can reflect well on your character and fit within the company.

By following these tips, you can present yourself as a strong candidate who is not only technically proficient but also a great cultural fit for 23andMe. Good luck!

In this section, we’ll review the various interview questions that might be asked during a software engineering interview at 23andMe. The interview process will likely focus on your technical skills, problem-solving abilities, and cultural fit within the team. Be prepared to discuss your past experiences, technical challenges you've faced, and how you approach software development.

Technical Skills

1. Can you describe a technical challenge you faced in a previous project and how you resolved it?

This question aims to assess your problem-solving skills and ability to overcome obstacles in software development.

How to Answer

Provide a specific example that highlights your analytical thinking and technical expertise. Discuss the challenge, your approach to solving it, and the outcome.

Example

“In a previous project, we faced performance issues with our database queries. I analyzed the slow queries and identified that we were not using indexes effectively. I implemented indexing strategies and optimized our queries, which improved the performance by 40%.”

2. How do you ensure the quality of your code?

This question evaluates your commitment to writing maintainable and high-quality code.

How to Answer

Discuss your practices for code reviews, testing, and continuous integration. Mention any tools or methodologies you use to maintain code quality.

Example

“I follow a strict code review process where I encourage my peers to provide feedback. I also write unit tests for my code and use CI/CD pipelines to automate testing, ensuring that any new code meets our quality standards before deployment.”

3. Explain a time when you had to work with a difficult team member. How did you handle it?

This question assesses your interpersonal skills and ability to work in a team environment.

How to Answer

Share a specific instance where you faced a conflict and how you resolved it. Focus on communication and collaboration.

Example

“I once worked with a team member who was resistant to feedback. I scheduled a one-on-one meeting to discuss our project goals and how we could better collaborate. By actively listening to their concerns and finding common ground, we improved our working relationship and successfully completed the project.”

4. Describe your experience with cloud-based applications and APIs.

This question gauges your familiarity with cloud technologies and API design.

How to Answer

Highlight your experience with cloud platforms, the types of applications you've built, and your understanding of API design principles.

Example

“I have extensive experience designing RESTful APIs for cloud-based applications using AWS. I focus on creating scalable and secure APIs, ensuring they are well-documented and easy for other developers to integrate with.”

5. What programming languages are you most comfortable with, and why?

This question seeks to understand your technical background and preferences.

How to Answer

Discuss your proficiency in relevant programming languages and how they align with the role at 23andMe.

Example

“I am most comfortable with Python and JavaScript. Python’s versatility and strong libraries for data processing make it ideal for backend development, while JavaScript allows me to create dynamic user interfaces. I enjoy using both languages to build full-stack applications.”

System Design

1. How would you design a system to handle large-scale data processing?

This question tests your system design skills and understanding of scalability.

How to Answer

Outline your approach to designing a scalable system, including data storage, processing, and architecture considerations.

Example

“I would start by identifying the data sources and the volume of data we expect. I would use a distributed architecture with microservices to handle different components of the system. For data storage, I would consider using a combination of SQL and NoSQL databases, depending on the data structure, and implement a message queue for processing to ensure scalability.”

2. Can you explain the concept of CI/CD and its importance?

This question assesses your knowledge of modern software development practices.

How to Answer

Define CI/CD and explain how it improves the software development lifecycle.

Example

“CI/CD stands for Continuous Integration and Continuous Deployment. It allows teams to integrate code changes frequently and deploy them automatically. This practice reduces integration issues, ensures that code is always in a deployable state, and accelerates the release of new features.”

3. Describe how you would approach designing an API for a new feature.

This question evaluates your API design skills and understanding of user needs.

How to Answer

Discuss the steps you would take to gather requirements, design the API, and ensure it meets user needs.

Example

“I would start by gathering requirements from stakeholders to understand the feature's purpose. Then, I would design the API endpoints, focusing on RESTful principles, ensuring they are intuitive and well-structured. Finally, I would document the API thoroughly and gather feedback from potential users before implementation.”

4. What strategies do you use to optimize application performance?

This question looks at your ability to enhance application efficiency.

How to Answer

Share specific techniques you use to identify and resolve performance bottlenecks.

Example

“I use profiling tools to identify slow parts of the application and analyze database queries for optimization. Additionally, I implement caching strategies and load balancing to improve response times and handle increased traffic.”

5. How do you handle version control in your projects?

This question assesses your familiarity with version control systems and best practices.

How to Answer

Discuss your experience with version control systems, such as Git, and how you manage branches and releases.

Example

“I use Git for version control, following a branching strategy that includes feature branches for new developments and a main branch for stable releases. I ensure that all changes are reviewed through pull requests before merging, which helps maintain code quality and collaboration.”

Behavioral Questions

1. What interests you about working at 23andMe?

This question gauges your motivation and alignment with the company’s mission.

How to Answer

Express your enthusiasm for the company’s mission and how your values align with theirs.

Example

“I am passionate about using technology to improve health outcomes, and 23andMe’s mission to provide access to genetic information resonates with me. I believe my skills can contribute to meaningful projects that empower individuals to understand their health better.”

2. How do you prioritize tasks when working on multiple projects?

This question assesses your time management and organizational skills.

How to Answer

Discuss your approach to prioritization and how you ensure deadlines are met.

Example

“I prioritize tasks based on their impact and urgency. I use project management tools to track progress and communicate with my team to ensure alignment. Regular check-ins help me adjust priorities as needed to meet project goals.”

3. Describe a time when you had to learn a new technology quickly.

This question evaluates your adaptability and willingness to learn.

How to Answer

Share a specific instance where you successfully learned a new technology and applied it to a project.

Example

“When I was tasked with using Django for a project, I had no prior experience. I dedicated time to online courses and documentation, and within a few weeks, I was able to build a functional application that met our requirements.”

4. How do you stay updated with the latest technology trends?

This question assesses your commitment to professional development.

How to Answer

Discuss the resources you use to keep your skills current and how you apply new knowledge.

Example

“I regularly read tech blogs, participate in online forums, and attend webinars and conferences. I also enjoy experimenting with new technologies in personal projects, which helps me stay informed and apply what I learn.”

5. Can you give an example of how you’ve contributed to a team’s success?

This question looks at your teamwork and collaboration skills.

How to Answer

Provide a specific example that highlights your role in a team project and the positive outcome.

Example

“I led a team project where we developed a new feature for our application. I facilitated brainstorming sessions, ensuring everyone’s ideas were heard, and coordinated our efforts. The feature was well-received by users and significantly improved our application’s engagement metrics.”