1. Basics of API Testing
What is an API? Explain with an example.
What is the difference between REST and SOAP APIs?
Explain the difference between GET, POST, PUT, PATCH, DELETE.
What does it mean for an API method to be idempotent?
What is the difference between status codes 200, 201, 400, 401, 403, 404, 500?
2. Practical API Testing
How do you send a GET request using Python (requests library)?
How do you send a POST request with JSON payload?
How do you add headers (like Authorization or Content-Type) to a request?
How do you validate response body using Python?
How do you check response time and status code in API testing?
3. Authentication & Security
What is API authentication? Explain Basic Auth, OAuth, and JWT.
How would you test an API that requires a token?
What is CORS and how does it affect API testing?
How do you test API endpoints for unauthorized access?
How do you handle API rate limiting in tests?
4. Automation & Tools
Which tools are commonly used for API testing? (Postman, SoapUI, RestAssured, etc.)
How do you automate API tests in Python?
How do you create data-driven API tests?
How do you assert JSON schema in API responses?
How can you chain multiple API requests in an automated test?
5. Advanced API Testing
How do you test APIs with query parameters and path parameters?
How do you handle dynamic data in API requests/responses?
How do you test API endpoints under load/stress?
How do you test APIs for edge cases or invalid inputs?
Explain how to test asynchronous APIs or webhooks.
6. Troubleshooting & Debugging
How do you debug a failing API test?
How do you capture logs for API requests/responses?
How do you test APIs when the backend database is not ready?
How do you validate headers, cookies, and response content type?
What are common reasons for API failures and how to identify them?