General Backend Engineering Interview Questions
1. System Design Questions
• How would you design a URL shortening service like Bitly?
• Design a scalable messaging system similar to Slack or WhatsApp.
• How would you design a rate-limiting feature for an API? Discuss implementation and edge cases.
• Explain how you would build a notification service that can handle millions of users.
• Design a search engine backend that can index and search through large volumes of text.
2. Database and Storage
• Explain the differences between SQL and NoSQL databases. When would you choose one over the other?
• How would you design a schema for an e-commerce application (products, orders, customers)?
• What is database sharding, and when would you use it?
• Explain the concept of transactions in databases. What are ACID properties?
• How would you handle a scenario where a query is taking too long to execute?
3. API Development
• How would you design a RESTful API for a blogging platform?
• What are the main differences between REST and GraphQL? When would you use each?
• How would you implement API versioning? Discuss different strategies.
• What are common security practices you would implement when developing an API?
• Explain idempotency in HTTP methods and why it is important.
4. Performance and Scalability
• What techniques would you use to optimize a backend application that is experiencing high latency?
• How would you handle a sudden spike in traffic on your server?
• What is caching? How would you implement caching for a backend service?
• Explain the difference between horizontal and vertical scaling.
• How would you debug a backend application experiencing memory leaks?
5. Microservices and Distributed Systems
• What are the main differences between monolithic and microservices architectures?
• How would you handle communication between microservices? Discuss synchronous vs. asynchronous communication.
• Explain the concept of a distributed transaction. How would you implement it?
• How would you handle service discovery in a microservices architecture?
• What is eventual consistency, and how does it apply to distributed systems?
6. Concurrency and Threading
• How would you handle concurrent requests in a web server?
• Explain the difference between multi-threading and asynchronous programming.
• What are race conditions, and how would you prevent them in your code?
• How would you implement a thread-safe data structure in Python?
• What is the difference between a process and a thread? When would you use each?
7. Testing and Debugging
• How would you write unit tests for a REST API?
• What is integration testing, and how does it differ from unit testing?
• Explain how you would troubleshoot a production issue where the backend service is returning 500 errors.
• How would you handle logging in a microservices environment?
• What is a mock, and how would you use it in testing a backend service?
8. Security and Compliance
• Explain how you would implement user authentication and authorization in a backend application.
• What is SQL injection, and how can you prevent it?
• How would you implement data encryption in transit and at rest?
• What is CORS, and why is it important?
• How would you handle sensitive data such as passwords or API keys in your backend service?
9. DevOps and CI/CD
• How would you set up a CI/CD pipeline for a backend application?
• Explain the concept of containerization. How would you use Docker in a backend project?
• What is Kubernetes, and how would you use it to manage your backend services?
• How would you implement a zero-downtime deployment?
• How would you monitor the health of your backend services?
Scenario-based Questions
1. Debugging Scenario
• Your backend service is running slow during peak traffic hours. How would you approach diagnosing and resolving the issue?
2. API Failure
• An external API your service depends on is intermittently failing. How would you handle this in your backend to avoid downtime?
3. Database Migration
• How would you perform a live database migration without causing downtime?
