Cracking the eBay Software Engineer Interview: The Top Technical and Behavioral Questions

With over 182 million active buyers globally, eBay is a giant in the world of online commerce. Landing a software engineering role at this influential company is highly competitive

To help you shine in your eBay interview, I’ve compiled a list of the top technical and behavioral questions commonly asked, along with examples of strong responses

What Does an eBay Software Engineer Do?

As an eBay software engineer, you’ll be responsible for:

• Designing, developing and deploying high-quality software systems and applications
• Writing clean, maintainable and well-tested code
• Troubleshooting issues and bugs in existing software platforms
• Collaborating with cross-functional teams including product managers, designers and other engineers
• Continuously improving architecture, code quality and development practices

It’s a role that allows you to make an impact on global commerce through innovative solutions. But first, you have to ace the interview.

Technical eBay Software Engineer Interview Questions

Here are some of the most common technical questions asked along with tips on how to craft winning answers:

Tell me about your experience designing scalable systems.

This tests your ability to build systems capable of handling eBay’s massive scale. Demonstrate you understand common scalability challenges and solutions such as:

• Horizontal scaling by adding servers
• Implementing caching and load balancing
• Asynchronously processing tasks
• Optimizing queries and databases for efficiency

“In a previous role, I helped design a distributed system that scaled to handle over 150,000 concurrent users by implementing horizontal scaling, database optimization, and asynchronous job processing.”

How would you improve the performance of an existing application?

They want to ensure you can identify and resolve performance issues. Discuss your process such as:

• Profiling to pinpoint slow parts of the code
• Optimizing algorithms and queries
• Caching frequently accessed data
• Compressing responses
• Implementing CDNs and other infrastructure improvements

“I would begin by profiling the app to isolate any inefficient code or costly operations. Then I’d look for optimization opportunities, like implementing caching to avoid redundant database calls or compressing API responses. If major infrastructure changes were needed, I’d present benchmarks to justify the investment.”

What principles and best practices do you follow when writing code?

This evaluates your ability to write high-quality, maintainable code. Share principles like:

• Writing DRY, modular code with separation of concerns
• Using readable naming conventions and code documentation
• Implementing proper error handling and logging
• Optimizing for performance
• Writing tests and committing frequently

“I adhere to several key principles including modularity, separation of concerns, DRY code, and self-documentation through descriptive naming. I optimize for readability and maintainability rather than premature optimization. I also commit frequently and use thorough testing of both happy and unhappy paths.”

How would you improve the CI/CD pipelines for an enterprise-level application?

This tests your DevOps skills and ability to implement robust deployment strategies. Discuss improvements like:

• Implementing automated testing in the pipeline
• Adding staged rollouts to catch issues before full deployment
• Enabling quick rollbacks in case of problems
• Leveraging containerization and orchestration tools like Kubernetes
• Monitoring key metrics to gauge release quality

“I would focus on adding test automation early in the pipeline to improve code quality. Containerizing applications also makes deploys more reliable and standardized. Monitoring key metrics like user traffic, errors, and latency during a staged rollout helps assess release readiness before full deployment. Having quick rollback procedures in place reduces risk.”

What techniques or tools would you use to troubleshoot a problem in production?

Demonstrate your nimble debugging skills and ability to rapidly isolate and fix production issues.

“I would begin by reviewing application logs and traces to pinpoint the origin of the error. From there, I’d replicate the issue locally if possible to dig deeper into the specific cause. Tools like debuggers, APM solutions, and CPU profilers are invaluable for gaining visibility. I’d also communicate with users impacted to better understand the real-world effects.”

How would you improve the security posture of an existing codebase?

Security is paramount for eBay. Discuss ways to implement more secure practices like:

• Performing code audits to identify vulnerabilities
• Implementing input validation and output encoding
• Following the principles of least privilege and zero trust
• Encrypting sensitive data in transit and at rest
• Adding authentication and authorization controls
• Enabling security monitoring and testing in the SDLC

“I would start by conducting thorough code audits to uncover any security gaps, complemented by automated scanning tools. Implementing input validation and encryption of sensitive data would also be high priorities. I’d ensure we have security testing integrated in the development process and employ monitoring tools to identify threats in production.”

eBay Software Engineer Behavioral Interview Questions

Beyond technical skills, eBay also assesses your soft skills and cultural fit through behavioral interview questions. Here are some common ones with example responses:

Tell me about a time you influenced a key technical decision on your team.

This shows your ability to drive important decisions collaboratively. Share how you made a case for your approach using data/benchmarks, achieved buy-in across stakeholders, and arrived at an improved solution.

“As our team evaluated CMS options, I advocated for a React-based framework and created a prototype to demonstrate its advantages in flexibility, performance, and developer experience. I documented benchmarks and presented my case to senior management. This led to our team adopting React, which improved developer productivity.”

Describe a time you overcame a disagreement with a colleague. What was the situation and how did you handle it?

This evaluates your conflict management and emotional intelligence. Illustrate how you focused on understanding your colleague’s perspective, finding common ground, and compromising to reach a resolution.

“When a colleague and I disagreed on the technical approach for a product update, I asked them to share their reasoning and concerns. By having an open discussion focused on our shared goal of improving the product, we found a compromise that blended both our ideas. This led to a better solution than either of our initial proposals.”

Tell me about a time you made a mistake at work. What happened and how did you handle it?

They want to see you can acknowledge and learn from mistakes. Convey humility, transparency about the failure, and proactivity in preventing future issues.

“I once caused a production issue by overlooking a subtle edge case in my code. As soon as I realized my mistake, I alerted my manager and team to minimize impact. To prevent it going forward, I added more comprehensive test coverage and code reviews for complex logic. I now share this experience to remind my colleagues how small oversights can cause big problems.”

How do you balance delivering features quickly with writing high-quality, maintainable code?

This tests your ability to juggle competing priorities. Illustrate how you’ve optimized development workflows to enable both speed and quality.

“I identify opportunities to implement automation, like leveraging CI/CD pipelines and test suites, that improve quality while enabling faster release cycles. Writing modular, well-documented code also saves time down the road. I focus on architecting a scalable foundation upfront to allow for velocity further on. Most importantly, I communicate with stakeholders to align on appropriate time investments.”

Tell me about a time you had to rapidly learn a new technology or skillset. What did you do?

eBay needs engineers who can quickly upskill. Discuss how you dove into documentation and training, practiced hands-on build projects, and reached out to experts when getting ramped up on an unfamiliar tech stack or language.

“When I needed to quickly adopt React for a new project, I went through online courses to build a foundation. I practiced by developing sample components and iterating based on community/expert feedback. Pair-programming with experienced React developers also accelerated my learning. Within a few weeks, I had the core skills necessary to contribute features.”

Put It All Together and Ace Your eBay Interview

With an understanding of the top technical and behavioral interview questions, you can confidently take on the eBay interview process. Be sure to:

• Research the role and eBay product/tech stack in-depth
• Brush up on your knowledge of scalability, security, testing, and other key topics
• Prepare stories highlighting your collaboration and problem-solving
• Practice discussing your experience and projects out loud
• Articulate your passions for eBay’s mission

With the right preparation, you can land your dream role innovating the future of commerce at this dynamic company. Best of luck with your eBay interview!