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App Development
7 minutes read

Top REST API Testing Tools

By Jose Gomez
REST API testing tools
By Jose Gomez
App Development
7 minutes read

There are several excellent REST API testing tools available, but how do you know which one is best suited for your app development project? You won’t be able to avoid APIs, either. APIs are a critical part of modern mobile app development. Without API testing tools, applications would struggle to remain fully functional and secure. 

This post will highlight some of the critical aspects of an API testing tool your development team should consider when trying to choose the best solution for REST API tests. In addition, we will also explore some of the top API testing tools currently available. 

Choosing an API Testing Tool: Key Considerations 

Your organization will not have the time to thoroughly vet and test every API testing tool to find the one that is best suited for its projects. As a result, you will have to evaluate API testing tools based on considerations most important to your project and development team. Here are some ways to evaluate these testing tools:

  • Requirements
  • Complexity 
  • Integration with current systems 
  • Interoperability with management tools 


When evaluating API testing tools, the most crucial consideration is the requirements of your APIs. For example, does the testing tool in question support the majority of HTTP requests? If the API testing tool in question doesn’t support the HTTP requests most commonly used by the APIs in your project, it won’t be a good fit for your team. 

You will also want to know if a testing project’s settings, artifacts, and other elements can be imported into a new project to save time. Again, this facet might not be the most crucial consideration, but convenience is essential, especially when running many API tests in your project. 


Some API testing tools are more complex than others. Before you decide on an API testing tool, ensure your development team is comfortable with it and possesses the right skill set to use it effectively. The best practice would be to bring project management leaders into the decision-making process. That way, you choose a testing tool aligned with your team’s talent.

Integration with Current Systems 

Does your development team use CI/CD tools? Ensure the API testing tool you choose integrates with your current tools. If the testing tool does integrate with your current tools and systems, check to see if it is native. Native tools will not need to be configured. If the tool does not integrate natively, your team will need to spend extra time configuring everything to ensure the API testing tool functions as expected. 

Interoperability with Management Tools 

Development teams use a lot of different tools for communication and project management. An important aspect of API testing tools to consider is their interoperability with standard tools like Slack and Jira. For instance, imagine a scenario where a failing API test automatically creates a Jira issue pre-populated with relevant details and estimated Jira story points based on the test complexity. Interoperability simplifies daily tasks for your development team and ensures clear communication. The more tools you use, the more likely your team will miss a notification or action item. Interoperability ensures your teams stay fully connected. 

Top REST API Testing Tools to Consider 

There are too many API testing tools to cover all of them. However, we have compiled a list of REST API testing tools that your organization should strongly consider. Finding the best digital testing tools can be difficult, but if you use the key considerations we just covered, it will be easier to find the right tool for your organization. Here are some API testing tools to keep an eye on:

  • Katalon
  • REST-assured 
  • ReadyAPI
  • Postman
  • JMeter 


Katalon is a robust API testing tool that also enables users to test web and mobile applications. In addition, if you want to test SOAP APIs, you can also use the Katalon platform for these tests. Katalon supports native integration with CI/CD tools such as Docker, Jenkins, Azure DevOps, and more. 

The Katalon platform uses data-driven methods to automate API testing and ensure greater test coverage and reliability. Katalon allows testers to import API tests and projects from other popular API testing tools such as Postman. Katalon is a rare API testing tool that is great for both beginners and seasoned testing experts. 

This tool is free, but there are also paid versions that offer additional features and support services. 


REST-assured is an open-source Java Domain-specific language used to quickly test REST services. Typically, this tool is used to quickly verify and validate REST service request responses. Developers need not be experts in HTTP requests to get value out of this free tool. 

If your team uses the automation framework Serenity, REST-assured smoothly integrates with it to combine UI and REST testing in one place and generate visual reports. Despite being a free tool, REST-assured comes with several features and functions that allow testers to use it codeless. 


The ReadyAPI platform is used for more than REST API testing. ReadyAPI can be used for functional, security, performance, and load testing of RESTful, SOAP, GraphQL, and other popular web services. ReadyAPI is an easy-to-use API testing platform that will help your development team ensure the end-to-end functionality of all web services being used. 

ReadyAPI integrates with CI/CD pipeline tools and offers flexible test automation options. One of the best aspects of ReadyAPI is that it can be integrated with any development environment. Furthermore, it supports native integration with popular tools like Git, Docker, Jenkins, Azure DevOps, and more. 

ReadyAPI is an excellent tool for DevOps and Agile teams. This tool is not free to use like the others mentioned. However, ReadyAPI does offer different pricing plans. Explore the offered plans to find the best option for your business. 


Postman was originally a Chrome plugin but is now extended to a full REST client for Mac, Linux, and Windows operating systems. Postman might be the most accessible REST API testing tool to use that we included in this post. It has a rich User Interface and can be used for automated and manual exploratory testing. 

The Postman platform has recently added new user preferences that enable users to organize and share their tests, collections, results, and API elements with team members. This is the best platform for teams that want to promote knowledge sharing. Postman offers free plans, but your organization will have to pay a subscription fee once you start adding additional users. 


Initially designed for performance testing, JMeter is now used for functional API testing. JMeter is impressive because it supports offline test replays and results, native integrations with CI tools like Jenkins, and can still performance test static and dynamic resources. 

JMeter is best suited for testing APIs in web applications. This tool is free to use and open-source. It is not the most accessible tool for beginners, but as an open-source technology, a fair amount of documentation and support help is available. 

Final Thoughts 

There are several excellent API testing tools. Hopefully, now you have a better understanding of some of the most popular tools and how to evaluate if they are suitable for your business. If you want to learn more about REST API testing tools and your options, reach out to an experienced development partner

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