What is API Test Automation ? How to Test ?

What is API Testing?

To begin,Application Programming Interface(API) testing is a type of software testing that aims at validating the API Test Automation. It determines whether the APIs meet the expectations in terms of functionality, performance, reliability and security for an application. Most importantly,API tests mainly concentrate on the business logic layer of the software. It does not concentrate on the look and feel of an application. Instead of using standard user inputs -keyboard and outputs, API Test Automation uses software to send calls to the API, get output and the system’s response.

Set-up of API Test Environment

A test environment is a stack of technologies used for testing.
  • Use Testing Tool
  • Write own codes
  • Use the following:
  • Frisby.js – JavaScript-based API testing framework
  • REST-assured
  • Cypress.io – free front-end testing tool that has built-in features for API testing.
  • Postman tool was developed specially for API testing with asses to many assertions and easy syntax.

Points to be noted

  • Set up an initial environment that invokes API with a required set of parameters and then examine the test result.
  • Configure the Database and server.
  • Once the installation is done, call the API Function to check whether that API is working

API Testing Approach

Firstly, Start the API testing process with

  • a clearly defined scope of the program
  • understanding of how the API works
  • After that, apply various testing techniques along with test cases. API test cases define the conditions or variables to determine whether a specific system performs correctly and responds appropriately. Send request to the API with known to analyze the response that includes:

    • Data accuracy,quality
    • HTTP status code
    • Response,reply time
    • Authorization checks
    • non-functional tests results
    • How to Test API?

      API Testing Approach is a predefined strategy performed by the QA team. Perform the API testing after the build is ready. It does not include the source code.

        The three main steps of API testing:
      • Send the request with necessary input data.
      • Get the response having output data.
      • Verify the response returned as expected.

      API Testing approach

      • Understanding the functionality of the API program with properly defined program scope.
      • testing techniques – equivalence classes, boundary value analysis, and error guessing and write test cases.
      • Input Parameters to be planned and defined appropriately.
      • Test cases execution and comparing the results.
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      Best Practices of API Testing

      The most important best practices of API testing are:

      • When defining test cases, group them by category and include the selected parameters.
      • Develop test cases for every potential API input combination and reuse,repeat test cases to monitor the API throughout production.
      • Using manual and automated tests to produce better trustworthy consistent results.
      • Use API load tests to test the stress on the system.
      • Call sequencing with a solid plan.
      • Use a good level of documentation with automation.
      • Keep the test case as self-contained.

      Types of bugs found in API Testing

      • Duplicate or missing functionality
      • Improper messaging
      • Error handling mechanism is incompatible
      • Multi-threaded issues
      • Security, performance & security issues
      • Reliability issues

      How to do API Test Automation

      • ReadyAPI
      • ReadyAPI is a leading testing tool for functional, security, and performance/load testing of RESTful, SOAP, GraphQL, and other web services.

        The powerful tools are:

        • ReadyAPI Test
        • ReadyAPI Performance
        • ReadyAPI Virtualization


        Postman is the API testing platform for building and using APIs. This platform helps to create better APIs—faster. It integrates automated testing into your CI/CD pipeline.

        Micro Focus UFT

        Micro Focus UFT is the best tool to execute API Tests with simple UI and configuration.Unified Functional Testing (UFT) software is formerly known as HP QuickTest Professional (QTP). QTP supports Web, Java, .Net, Oracle, Siebel, Web-services, and many other major languages and platforms.

        Challenges of API Testing

        • Building irrelevant tests.
        • Parameter Combination, Parameter Selection, and Call Sequencing.
        • Leaving out response time assertions.
        • Difficulty in validating and verifying the output in a different system.
        • Testing APIs in a vacuum.
        • Managing API tests manually.
        • Exception handling function should be tested.


        Finally,Join API Testing has become absolutely vital with the rise of cloud applications. API Testing is an integral part of the software quality assurance process. Learn the right approach and tool to improve your testing career.

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