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Top 30 API Testing Interview Questions and Answers

22/June/2021 | 10 minutes to read


Here is a List of essential API Testing Interview Questions and Answers for Freshers and mid level of Experienced Professionals. All answers for these API Testing questions are explained in a simple and easiest way. These basic, advanced and latest API Testing questions will help you to clear your next Job interview.

API Testing Interview Questions and Answers

These interview questions are targeted for API Testing. You must know the answers of these frequently asked API Testing interview questions to clear the interview. For API Testing you should have some programming knowledge.

1. What is API?

API stands for Application Programming Interface which is a connection between computer programs or systems. API is a software interface that allows softwares to connect to each other. For example, When you browse Facebook then your browser makes calls to Facebook APIs to access the data. For more visit API.

2. What is API testing?

API Testing is a type of software testing which tests APIs for the correctness of functionality, performance, security and reliability. API testing is considered critical as APIs are primary interface to application logic. API testing is performed directly and in parts during integration testing. For more visit API Testing.

3. Does API testing require programming knowledge?

Yes, API Testing requires good knowledge of programming and coding.

4. Explain different HTTP status codes.

When a client makes serve request, server issues status code with response. These codes are classified into five categories:
  • 1xx informational response codes
  • 2xx success codes
  • 3xx redirection codes
  • 4xx client errors
  • 5xx server errors
For more visit HTTP status codes.

5. Explain the OOPs concept.

API testing requires some programming or coding knowledge and If you are using any Object Oriented Programming then you should have knowledge of OOPs concepts. OOPs concepts include object, class, methods, encapsulation, inheritance, Polymorphism, Abstraction and many more. We have written a separate article on OOPs concepts interview questions. For more visit OOPs Concept.

6. What are the types of web services?

7. Explain RESTful services.

8. What is the communication medium in REST API?

9. What are the different HTTP verbs?

10. Explain compile-time and run-time polymorphism.

11. What is JSON?

12. What is the difference between object and object reference?

13. Explain method over-riding.

14. Explain different API testing tools.

15. What are the steps for API testing?

Some General Interview Questions for API Testing

1. How much will you rate yourself in API Testing?

When you attend an interview, Interviewer may ask you to rate yourself in a specific Technology like API Testing, So It's depend on your knowledge and work experience in API Testing.

2. What challenges did you face while working on API Testing?

This question may be specific to your technology and completely depends on your past work experience. So you need to just explain the challenges you faced related to API Testing in your Project.

3. What was your role in the last Project related to API Testing?

It's based on your role and responsibilities assigned to you and what functionality you implemented using API Testing in your project. This question is generally asked in every interview.

4. How much experience do you have in API Testing?

Here you can tell about your overall work experience on API Testing.

5. Have you done any API Testing Certification or Training?

It depends on the candidate whether you have done any API Testing training or certification. Certifications or training are not essential but good to have.


We have covered some frequently asked API Testing Interview Questions and Answers to help you for your Interview. All these Essential API Testing Interview Questions are targeted for mid level of experienced Professionals and freshers.
While attending any API Testing Interview if you face any difficulty to answer any question please write to us at Our IT Expert team will find the best answer and will update on the portal. In case we find any new API Testing questions, we will update the same here.