API Testing Interview Questions and Answers for 10 years experience

0
100 API Testing Interview Questions & Answers

  1. What is API testing and why is it important?

    • Answer: API testing is a type of software testing that focuses on verifying Application Programming Interfaces (APIs). It involves sending requests to the API and checking the responses to ensure the API functions correctly, securely, and reliably. It's important because it allows for early detection of bugs, improves overall software quality, increases test coverage, enables faster testing cycles, and allows for testing independent of the UI.

  2. Explain the difference between REST and SOAP APIs.

    • Answer: REST (Representational State Transfer) and SOAP (Simple Object Access Protocol) are both architectural styles for building APIs, but they differ significantly. REST is lightweight, uses various data formats (JSON, XML), is stateless, and typically uses HTTP methods (GET, POST, PUT, DELETE). SOAP is more complex, uses XML for data exchange, is often stateful, and relies on protocols like HTTP or SMTP. REST is generally preferred for its simplicity and scalability.

  3. Describe different API testing methods.

    • Answer: Common API testing methods include:
      • Unit Testing: Testing individual API components.
      • Integration Testing: Testing the interaction between multiple API components.
      • Contract Testing: Verifying that the API adheres to its defined contract.
      • Functional Testing: Validating that the API performs its intended functions.
      • Load Testing: Assessing the API's performance under heavy load.
      • Security Testing: Identifying vulnerabilities in the API.
      • Performance Testing: Evaluating response times, throughput, and resource usage.

  4. What are the common HTTP methods used in API testing? Explain their use.

    • Answer: GET, POST, PUT, DELETE, PATCH are the most common. GET retrieves data, POST creates new data, PUT updates existing data, DELETE removes data, and PATCH partially updates data.

  5. How do you handle API authentication in your tests?

    • Answer: Common methods include API keys, OAuth 2.0, JWT (JSON Web Tokens), basic authentication, and token-based authentication. The approach depends on the API's security requirements. I typically use environment variables or configuration files to store sensitive credentials and avoid hardcoding them in the test scripts.

  6. Explain how you would test for API security vulnerabilities.

    • Answer: I would test for vulnerabilities like SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF), broken authentication, sensitive data exposure, and insecure direct object references. Tools like OWASP ZAP and manual testing techniques are crucial. I would also pay close attention to input validation and output encoding.

  7. What tools and technologies are you familiar with for API testing?

    • Answer: [List specific tools used, e.g., Postman, REST-assured, SOAPUI, JMeter, Karate DSL, Swagger/OpenAPI, etc. Tailor this to your actual experience.]

  8. Describe your experience with API automation frameworks.

    • Answer: [Describe specific frameworks used, such as REST-assured with Java, pytest with Python, etc., detailing the framework's structure, advantages, and challenges encountered.]

  9. How do you handle different response codes in your API tests?

    • Answer: I assert that the API returns the expected HTTP status code (e.g., 200 OK, 404 Not Found, 500 Internal Server Error). I also examine the response body to validate the data according to the specific HTTP status code. For example, a 200 OK should return the correct data, while a 404 should return an appropriate error message.

Thank you for reading our blog post on 'API Testing Interview Questions and Answers for 10 years experience'.We hope you found it informative and useful.Stay tuned for more insightful content!