Q1
Design a REST API endpoint for a user authentication system. Walk us through your approach to database schema, request/response handling, security considerations (hashing, JWT tokens), and rate limiting.
Why they ask this:* Evaluates your understanding of API design fundamentals, security best practices, and real-world implementation decisions critical to backend development.
Q2
Explain the differences between SQL and NoSQL databases with specific examples. When would you choose one over the other for a real production system, and what trade-offs are involved?
Why they ask this:* Tests your knowledge of data persistence patterns and ability to make architectural decisions based on project requirements and scalability concerns.
Q3
You have a database query that takes 8 seconds to execute and impacts user-facing endpoints. Walk us through your debugging process: how would you identify the bottleneck and implement solutions (indexing, query optimization, caching strategies)?
Why they ask this:* Assesses practical problem-solving skills, proficiency with performance monitoring tools, and knowledge of optimization techniques essential for mid-level backend engineers.
Q4
Describe how you would design a system to handle background jobs or asynchronous tasks (e.g., sending emails, processing payments). What tools, patterns, or frameworks would you use and why?