6 Top Free API Testing Tools of 2019 Share on X


4. Katalon Studio


Katalon Studio is automation testing tool to support Web UI functional, API/Web services, and Mobile testing.

Katalon Studio provide support for SOAP and RESTful service requests with various types of commands (GET, POST, PUT, DELETE) and provides parameterization capability.

Key Points:

  • Support both SOAP and RESTful API testing.
  • Provide hundreds of built-in keywords for writing test cases.
  • Provide support for AssertJ, one of the most powerful assertion libraries to create fluent assertions via BDD style.
  • Suitable for both pros via custom scripting using Groovy and non-techies via Manual.
  • Support API, Web GUI and Mobile testing all at one place.
  • Support data driven testing approach.
  • It can be used for automated and exploratory testing.
  • Provide CI/CD integration support.

Website: https://www.katalon.com

Pricing: Free


5. JMeter


JMeter is an open-source tool. Built for load testing but it is widely popular among the testers for functional API testing as well.

QA engineers can take great benefit out of this tool as it provides all sorts of functionality which are required to test an API.

Key Points:

  • JMeter automatically works with CSV files which allows the team to quickly create unique parameter values for API tests.
  • JMeter supports integration with Jenkins which means we can include API test in CI pipelines.
  • JMeter supports both static as well as dynamic resources performance testing.


Website: https://jmeter.apache.org/

Pricing: Open source

6. Karate DSL


Karate DSL is pretty new API testing tool in the market and helps to write scenarios for API-based BDD tests quite simple. One of the advantages is that you don’t need to write step definitions unlike other BDD frameworks like Cucumber, JBehave etc. exclusively.

Key Points:

  • It is built on top of Cucumber JVM.
  • Tests are easy to write even for non-programmers.
  • It supports multi-threaded parallel execution.
  • You can generate reports just like any other standard Java project.
  • If you are already using Java and Cucumber in your project, then KarateDSL might be a great choice.


Website: https://github.com/intuit/karate

Pricing: Open Source

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  • Deepak Verma

    Deepak Verma is a Test Automation Consultant and Software development Engineer for more than 10 years. His mission is to help you become an In-demand full stack automation tester. He is also the founder of Techndeck, a blog and online coaching platform dedicated to helping you succeed with all the automation basics to advanced testing automation tricks.

    http://Techndeck.com deepak.rkgit@gmail.com Verma Deepak