API Application Programming Interface Testing

To understand API Application Programming Interface Testing, we must first understand what API is all about. As you might have already guessed, API is an acronym of Application Programming Interface. An API is something that facilitates communication between two software systems making data relay possible.

An API Application Programming Interface consists of a sequence of program and functions that are executed at a different software system.

API Application Programming Interface Testing

Unlike GUI Testing, API Application Programming Interface Testing does not focus on the look and feel of the said application program. We are not dealing with standard input and outputs mechanism here, rather we are supposed to perform testing by using a software to send a call to the API and grab the output from there.

So, the real things are happening in the background. We are making API calls and taking responses to check whether the said functionality is working or not. It is also renowned as “headless testing” since it helps us to test all the headless technologies like Web Service, JMS, HTTP and Databases.

API Testing works on the business layer that is sandwiched between Presentation Layer (where GUI Testing happens) and Database Layer (from where you retrieve data).

To perform API Application Programming Interface testing you need a tool that drives your APIs. You also have to write a code to test those APIs.

Important Points to Remember

Here are some key points to remember:

• You are basically performing End to End Testing here.
• You cannot access the source code.
• Focus is on the functional aspect of the code.
• API Testing is performed after build is created.

Before beginning the whole API testing process, you need to set up the initial environment. Since you are not dealing with GUI here, it is a tad difficult to do that. We need to configure the database and server before proceeding as per the requirements, of course. After the installation, we need to check whether basic API functionalities are working or not.

Tools to Perform API Testing

There are tons of tools that help you to perform API Testing. Some of them have been mentioned below:

1. SOAPUI
2. Postman
3. Karate DSL
4. Parasoft
5. HttpMaster Express
6. Runscope
7. Curl
8. Cfix
9. Check
10. CTESK
11. dotTEST
12. API Fortress
13. Tricentis

If you are working for the first time on a said tool, the primal challenge you might face could be related to parameter selection, combination and sequencing. The fact that there is no UI entailed could make things difficult.

Well don’t worry! That’s why I am here for to dumb down things for you and make things easier to understand.