Top API Testing interview questions

Application programming interfaces (APIs), are also known as the building blocks of web applications and also the key enablers of digital transformations for enterprises.

API testing helps to verify and validate the functionality and behavior of interfaces through manual or automated request generations and verify the corresponding published responses to check for the accuracy of APIs.

In this article, we will cover six important and most common API interview questions that you can face in your API testing interview.

So let’s begin.

1. What is an API

API is an acronym for Application Programming Interface and is a set of routines, protocols, and tools for building Software Applications. APIs define how one software program should interact with another software program. In simple words, API helps two software applications communicate with each other.

2. What are the most commonly used status codes in API testing

The most commonly used status codes in API testing include

200 - success/OK

201 - CREATED - used in POST or PUT methods when the resource is created.

401 - FORBIDDEN - This occurs when the user does not have access (or is forbidden) to the resource.

404 - NOT FOUND - The resource method is currently not available.

500 - INTERNAL SERVER ERROR - This occurs when the server throws some exceptions while running the method.

502 - BAD GATEWAY - In this case, the server was not able to get a response from another upstream server.

3. What are the essential HTTP methods required in Testing

GET: It helps you to retrieve data from a server

POST: It helps you to send data to a server or to create/update a resource.

PUT: It helps you send data to a server or create/update a resource.

DELETE: It helps you delete data from a server

PATCH: It is used while partial modifications to a resource

4. What are the common API testing types

Some of the common API testing types include

1. Unit testing

2. Functional testing

3. Load testing

4. Security testing

5. UI testing

5. State some Tools for API testing

Following are some of the tools used for API testing.

1. Rest-Assured

Rest-Assured is an open-source Java library that provides a domain-specific language (DSL) that helps in testing RESTful APIs. It supports XML and JSON Requests/Responses for API testing.

1. Postman

Postman is a popular tool used for API testing. It is available as a free version as well as a paid version. Postman provides an easy-to-use interface.

1. Katalon Studio

Katalon Studio supports test scenarios that use web services and can be used as an API testing tool.

1. Jmeter

Jmeter is one of the most popular and simple tools to perform API Testing.

6. Some of the API examples that are popular

Some of the popular API examples include weather APIs, Google Maps APIs, Twitter APIs, Amazon Advertising APIs, and others.

Conclusion:

In this article, we saw some common questions that you should be aware of before answering an interview related to API testing. The API market is booming across Finance, Telecom, Manufacturing, Healthcare, Hospitality, and other sectors and so API testers will be in demand for some time.

At Testrig Technologies, our QA experts are well-versed in API technology and use manual and automated testing techniques to test the APIs.

To know more about our API testing services contact us at Testrig Technologies.

I am Ashwini Lanje representing Testrig Technologies - A software testing and Quality Assurance company in the Usa