API is the acronym for Application Programming Interface which facilitates easy communication of software components.
It’s a connecting bridge between distributed and complex programs to build an ecosystem of apps that exchange data to fulfill the customer’s requirements.

With API testing, several requests to validate the response and guarantee the API’s reliability, safety, & performance.
Generally, API testing gets expensive and doesn’t provide an immediate return on investment. However, it’s an essential process that every developer uses and ignores the expense.
Let’s dive in and understand more!

## What is API testing?

API testing is a type of software testing that helps in testing individual API methods & interactions of APIs. It’s a type of testing that is performed in the integration phase, after unit testing finishes, and before user interface testing starts. It’s used to ensure that the API is working as per the guidelines and that system requirements are fulfilled. This type of testing can be performed easily using automated testing tools.

Here’s the list of some common tasks that are executed during API testing:

• Testing functions of an API to make sure its behavior is as per the user’s expectations
• Perform the testing for overcoming security vulnerabilities
• Check and ensure that the API is returning the correct response even when the input is different
• Check if the validation and error handling are done correctly
• Verify the scalability and performance of the API

API testing is essential as it ensures that different components of the system can communicate easily with each other; also if the system can handle large volumes of requests or not.

Common steps of API testing

The process of API testing is essential as it helps you to ensure the different systems that make a whole app are working correctly together. Also, this process helps in verifying that the data that’s exchanged is secure and accurate. It also helps in finding and fixing issues before the app is deployed in production. Here are the common steps of API testing:

• Writing test cases that exercise the various functions of an API
• Reviewing the API docs to know the expected input/output and functionalities of the same
• Running the written test cases and then comparing the actual output with the expected output
• Reviewing the results and searching for any issue that has to be solved

## Advantages of API Testing

• API testing helps to look for and fix the bugs early before they can create a huge impact on the final app/software
• It ensures that APIs work as per the expectations, provide accurate results, and follow the given rules
• API testing increases the security by verifying the authentication, data protection, and API authorization
• It also validates the performance metrics such as ensuring the execution of the system, response time, managing multiple users, etc
• Companies can have high-quality software that makes the customers happy, and minimizes the risk of software failures, by using API testing.
• It also helps the team to have different software systems to communicate and speed up the development
• Through thorough API testing, you can simply ensure seamless integration and strong operation of software apps that can rely on APIs.

What are the reasons for which we use API testing?

Here are the main tests that we perform during API testing:

• Checking the response time of the software
• Verifying the data accuracy
• Check whether any functionality is missing
• Performance and security issues are to be solved
• Verifying Authorization
• Write error codes if the API returns
• Check and solve the reliability issues These are some of the main reasons to perform API testing.

Types of API testing

Many types of API testing are most often used for performing different testing together. It is also possible to test the APIs simultaneously. So, here’s the list that shows different types of API testing:

• Integration testing
• Unit testing
• Performance testing
• End-to-end testing
• Security testing
• Functional testing
• Load testing
• Reliability testing
• Penetration testing
• Fuzz testing By using any of these types of API testing as and when required, you can easily test different APIs belonging to different types. So, the things that we discussed here will help you get a basic idea about API testing.

Final Words

We hope that this article has given you the main idea about what API testing is, and how it helps to ensure that your app interface is reliable. Through performing different types of tests and other processes, you can ensure that your app is fully functional too as per the requirement of the user.