API (Application Programming Interface) is a registering point of interaction that empowers correspondence and information trade between two separate programming frameworks. A programming framework that executes a Programming interface incorporates a few capabilities/subroutines that another product framework can perform. API interface characterizes demands that can be made, how to make demands, information designs that can be utilized, and so forth between two programming frameworks. 

What is API Testing? 

API TESTING is a product testing type that approves Application Programming Connection points (APIs). The motivation behind API Testing is to actually take a look at the usefulness, unwavering quality, execution, and security of the programming points of interaction. In API Testing, rather than utilizing standard client inputs(keyboard) and yields, you use programming to send calls to the Programming interface, get results, and note down the framework’s reaction. API tests are totally different from GUI Tests and won’t focus on the look and feel of an application. It mostly focuses on the business rationale layer of product engineering. 

API automation Testing requires an application that can be interacted via an API. In order to test an API, you will need to: 

  • Use Testing Tool to drive the API 
  • Write your own code to test the API 

How to Set up API Test environment 

  1. API Testing is not the same as other programming testing types as GUI isn’t accessible, but you are expected to arrange a beginning environment that summons API with a necessary arrangement of boundaries and afterward at last inspects the test outcomes. 
  1. Consequently, setting up a testing climate for API automation testing appears to be somewhat intricate. 
  1. Database and server ought to be arranged according to the application prerequisites. 
  1. When the establishment is finished, the API Capability ought to be called to actually take a look at whether that API is working. 

Types of Output of an API 

An output of API could be 

  1. Any type of data 
  2. Status (say Pass or Fail) 
  3. Call another API function. 

Test Cases for API Testing: 

Test Cases for API testing depend on the following: 


  1. Return value based on input condition: It is generally simple to test, as info can be characterized and results can be confirmed. 
  2. Does not return anything: When there is no return esteem, a way of behaving of API on the framework to be checked 
  3. Trigger some other API/event/interrupt: On the off chance that a result of a Programming interface sets off some occasion or intrudes on, those occasions and intrude on audience members ought to be followed 
  4. Update data structure: Refreshing information design will significantly affect the framework. 
  5. Modify certain resources: In the event that an API call alters a few assets, it ought to be approved by getting to separate assets. 
  6. API Testing Approach 

API Testing Approach is a predefined technique or a strategy that the QA group will act to lead the API testing after the form is prepared. This testing does exclude the source code. The API testing approach assists with bettering comprehending the functionalities, testing methods, input boundaries, and the execution of experiments. 


API comprises a bunch of classes/capabilities/strategies which address the business rationale layer. On the off chance that API isn’t tried as expected, it might bring on some issues in the API application as well as in the calling application. It is an imperative test in programming.