13. How do you perform performance testing on APIs?
Answer:
- Use tools like JMeter, Apache Bench, or Locust
- Simulate concurrent users
- Measure response times, latency, and throughput
14. What is concurrency testing in API testing?
Answer: It tests the behavior of APIs when multiple users perform actions simultaneously. It ensures data integrity and no deadlocks.
15. What are test coverage criteria in an API Test Plan?
Answer:
- Functional Coverage
- Data Validation Coverage
- Error Handling
- Performance and Load Testing
- Regression Coverage
16. What are the risks in API testing and how do you mitigate them?
Answer: Risk: Poor documentation
Mitigation: Ensure access to up-to-date API specs
Risk: External API dependency
Mitigation: Use mock servers during testing
17. How do you structure an API Test Plan for maximum efficiency?
Answer:
- Define test objectives
- Identify endpoints and methods
- Prepare test data
- Categorize test types (Functional, Security, Load, etc.)
- Define roles and responsibilities
- Implement defect triage and tracking
18. How do you ensure backward compatibility in APIs?
Answer:
- Versioning of APIs
- Regression testing on older clients
- Proper deprecation policy
19. What is the role of exploratory testing in an API project?
Answer: Exploratory testing uncovers hidden defects through unscripted test sessions, often revealing issues missed in structured testing.
20. What documentation do you verify as part of API testing?
Answer:
- Swagger/OpenAPI specifications
- Endpoint definitions
- Request/response schemas
- Status codes
- Sample payloads
Bonus Tips for Interview Preparation:
- Practice using Fake REST APIs with Postman.
- Review Swagger documentation.
- Prepare example test cases for all CRUD operations.
- Focus on test strategy and risk mitigation techniques.
