Mid leveltech

Backend Developer
Interview Questions

Covering Backend Developer interview questions — APIs, databases, system design, and scalability prep.. Free, no signup required.

10 questions ready

Q1
Design a REST API for an e-commerce platform that handles product listings, user orders, and inventory management. Walk us through your approach to database schema, caching strategy, and how you'd handle concurrent requests during high traffic periods.
Why they ask this:* Assesses ability to design scalable systems, understand database optimization, caching layers, and concurrency handling—core skills for backend engineers at mid-level.
Q2
Explain the difference between SQL and NoSQL databases, and describe a scenario where you would choose one over the other. What trade-offs would you consider?
Why they ask this:* Tests knowledge of fundamental data storage concepts and the judgment to select appropriate technologies based on use case requirements.
Q3
You have a microservices architecture with multiple services communicating via REST APIs. How would you implement and handle service-to-service authentication and authorization?
Why they ask this:* Evaluates understanding of modern backend architecture patterns, security best practices, and complexity of distributed systems.
Q4
Write or explain the logic for a function that detects and removes duplicate records from a large dataset efficiently. What data structures and algorithms would you use?
Q5
Tell me about a time when you discovered a critical bug in production. What was the situation, what steps did you take to diagnose it, how did you fix it, and what did you learn?
Q6
Describe a project where you had to refactor legacy code or improve system performance. What was your approach, what challenges did you face, and what was the outcome?
Q7
Tell me about a time when you disagreed with a team member on a technical decision. How did you handle it, and what was the resolution?
Q8
How would you handle a situation where a new feature request requires significant architectural changes, but the product team wants it shipped in two weeks? What trade-offs would you propose?
Q9
What would you do if you deployed code that caused a 30% increase in database query latency affecting thousands of users, and you need to resolve it immediately?
Q10
How would you approach taking over a backend system that has minimal documentation, inconsistent code style, and no automated tests?
🔒

7 questions locked

Upgrade to unlock all 10 questions with answer guides, videos & PDF

Upgrade to unlock →

Want questions tailored to a specific company?

Try the full generator →