The best way to evaluate the APIs built by the developers is to use the right API testing tool. But there are too many API testing tools in the market and this is why making the right choice is a bit confusing. Well, this is why we are here to showcase some of the leading API testing tools that can perfectly serve your purpose. But before that, we must orient a little with the need of using API testing tools. 

Why Carry Out API Testing?

Since the latest performance-focused development methodologies such as continuous integration (CI), continuous deployment (CD), and DevOps have become tremendously popular among the development companies, testing and feedback mechanisms should work as quickly as possible. Without faster testing and feedback tools the gain in respect of UI automation can be fully wasted. 

Now since APIs are considered to be building blocks in the software development process, the APIs must function smoothly. With the help of faster API testing, the quality of software applications can easily be guaranteed. On the other hand, several complexities are involved in the API testing process and this is exactly where automation API testing tools can play a significant role.

Let us now explain some of the most popular and time tested API testing tools in the market. 


REST-Assured is a fluid Java-based library that can be used for testing all the REST services based on HTTP. The tool is fully designed to address a multitude of testing requirements. The base thing about the tool is that it can easily collaborate with other Java-based automation frameworks. 

The tool offers a behavior-driven development (BDD) protocol allowing easier testing of APIs in Java. Moreover, the tool comes loaded with an array of ready to use functionalities that prevent developers from coding the test program from basics. For all the teams comprising the majority of Java developers, this testing tool can be highly applicable. 


Are you looking for a faster testing tool that doesn’t require going through all the overhead considerations? Or do you need an API testing tool that just explores the effectiveness of it without going deep into the code of the app? Well, Postman appears to be the right tool for such needs. 

Postman is actually a REST client that can be used through its own Chrome plugin. The tool is also available with respective native Mac and Windows versions. Postman coming with an easy to use interface makes things easier for the entire developer team. 


Postwoman is just another great testing tool for modern APIs with many similarities with the Postman. It boasts of a superbly easy and rich UI helping with API requests at a faster pace. 

Some of the key features that make Postwoman a great API testing tool include the capability of running everything online without installation, multiple platforms and device support, the accessibility from anywhere, and easier customization. You can begin using this tool without requiring to install the software. 


This is a more advanced tool suited for complex API testing contexts that to a great extent carry out responsibilities similar to QA test professionals. SoapUI is an ideal testing tool for all the teams that do a lot of API testing.

The tool is fully featured and completely made for the purpose of API testing. So, in case you need a comprehensive solution and want to do away with the huge development task of building something from scratch, this comes as a great solution.


JMeter was originally built for the purpose of load testing. But over the years, developers started using JMeter for API testing purposes as well. The tool offers all the features and functions that developers need to carry out API testing. In addition, the tool also provides an array of other advanced features to help you with your testing efforts. 

Some of the capabilities that made JMeter popular include its ability to use CSV files, integration of Jenkins, and several others. The tool which is already known for performance and load testing can be utilized as a part of a larger testing process. 


Karate is a highly reliable tool with several unique features and functions. Some of the unique capabilities of this tool include regular API testing, API performance, and load testing and API testing doubles. Just with one tool developers great all the things they need for testing. 

From the last Karate update, UI test automation support is also available with the tool and thus Karate became the most comprehensive testing framework for addressing a variety of testing needs. 


Fiddler is a great testing tool for modern APIs that allows developers to keep a watch on HTTP requests as well as make use of them when required. It is a kind of tool that besides debugging a web API can also help fulfilling other testing objectives.

The tool comes equipped with the APITest extension for evaluating the web API behavior. You can also make use of the FiddlerCore.NET class library for developing the API testing infrastructure. If your development team is dominated by the presence of .Net developers, it can be the right choice as a testing tool. 

Citrus Framework

Citrus is a great testing framework allowing developers to run integration tests automatically. It is a feature-rich tool that can address the testing requirements of different types. 

Some of the key benefits of this testing tool include the capability to work with REST, SOAP, HTTP, JMS, TCP/IP, and several other protocols, creation of tests using

Java or XML, very detailed documentation, and frequent updates. 


PowerShell emerged as a great tool in development companies where DevOps has been embraced as a development methodology. The tool offers great testing benefits for developers opting for automation. 

Some of the important benefits of using the PowerShell tool for the purpose of API testing include no need for a lot of code either for importing Web Services Description Language or sending requests, being ore-installed in Windows hardware, lower learning curve, the capability to run directly in the command line, etc.  


Insomnia is a truly developer-friendly and easy tool that comes with a beautiful and engaging interface. The tool is also rich with several key features required for modern API testing. 

Some of the key features and functions this tool comes loaded with include the ability to create HTTP requests, seeing response details, arranging the tests, reading the values, and producing code snippets. 


This is high time to admit that no API testing tool is perfect and comprehensive enough to take care of all testing requirements. Naturally, not all developer teams cannot be satisfied with any specific testing tool. This is especially why developers need to look deeper and research well about the underlying features, capabilities, and testing scopes of each tool. Apart from these listed tools, obviously there are many that developers can keep inquiring about.

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