Top 8 Testing Tools for API Testing

API (Application Programming Interface) is a type of software testing in which testing is performed on APIs to check their reliability, performance, functionality, and security. Due to the growing number of interconnecting platforms and cloud applications, it becomes essential to test the API because many of the services that we use in our daily routine are entirely dependent on the application programming interface.

API is a particular set of functions that helps applications to interact with operating systems, microservices, and external software components. Moreover, it allows developers to move their data in the cloud and access the information anytime. In other words, the role of API is to deliver a user response to a system and the system further gives the back response to a user. Thus, in case of missing the API testing process, your service may not work.

In this blog, we have prepared a list of the top 8 testing tools for API testing that you can discover below.

1. SoapUI
2. Postman
3. Test Mace
4. RapidAPI testing
5. Katalon Studio
6. Burp Suite
7. REST-assured
8. JMeter

1. SoapUI

SoapUI is one of the best API testing tools used by the popular API testing companybecause it allows developers to run their complicated test cases and make their app successful. It allows easy integration of APIS and comes in two editions that are community edition and pro edition. The community edition is suitable for scanning SOAP and Rest APIs. Whereas, the Pro edition is suitable for the testing of microservices, SOAP, REST, GraphQL, and other back-end services.


  • It can develop custom codes using Groovy.
  • It supports asynchronous testing and allow to create a test like drag and drop features.
  • It can update the requests automatically.
  • It can generate reports in various formats.
  • Due to the easy extraction of data, it ensures easy tracking of improvements and lets the testers perform effective testing based on the latest trends.
  • It allows us to load data from databases and excel files.
  • Thousands of worldwide companies, including Cisco, Apple, Microsoft, Oracle, Intel, and HP use this API testing tool because it is easy to integrate with 13 API management platforms and provides compatibility for IoT, JMS, REST & SOAP.
  • It enables you to reuse your functional test cases as load tests and scan the security within quick minutes.

2. Postman

Postman was initially launched as a Chrome Plugin, but now it is used as a top-tier API testing tool to test the API without writing code in an integrated development environment. If you want to perform this type of testing, you can hire API testers because they know how to write Boolean tests effectively within the Postman interface. It allows them to create several REST calls and they know how the functions are performed in the tool. It is used for integrating and interacting with APIs. Both testers and developers can use it to export and import the collection.


  • It supports various platforms like Linux, Chrome, Mac, and Windows.
  • There is no need to learn a new language for running the test cases in Postman.
  • It is cost-effective, user-friendly, and extremely suitable for automation testing.
  • It not only helps you get the testing part done but also gives you the freedom to monitor the features, and check the document.

3. Test Mace

Test Mace is another best tool for APItesting services. It is a modern and very powerful cross-platform tool that you can use in your company to create automated API tests.


  • Performing testing with complex scenarios is easy.
  • It helps you create tests without doing actual programming.
  • The main features of Test Mace are API import, variables, syntax highlighting, share button, generation of tests, and autocompletion.
  • It has a well-organized project structure and a human-readable file format that allows you to work on your project, review the test cases and perform the changes with undo and redo functions.
  • It has an advanced in-built code editor that supports javascript tests.

4. RapidAPI Testing

If you want to be the best API testing service provider in India, the RapidAPI testing tool is what you need for creating and managing detailed API tests from the development to the deployment stage. It helps you run any type of APU from SOAP, REST to GraphQL. It provides the ease of global monitoring, comprehensive testing, and seamless integration.


  • It is beneficial for conducting unlimited tests and up to 100,000 API calls.
  • It can be used for CI/CD integration from Jenkins, GitHub, Travis, Gitlab, and CircleCI.
  • It gives real-time notification through emails, SMS, etc.
  • It allows you to run tests consistently and help you monitor APIs with various geographies.
  • It ensures comprehensive testing, automated testing, functional testing, and performance testing all in one product.

5. Katalon Studio

Katalon Studio is a free-license tool disclosed to the market in January 2015 with a Selenium-based engine. It is specialized in creating and reusing automated test scripts for UI without writing any code. It is suitable for implementing automated tests of UI elements, including iFrames, pop-ups, and wait-time. You can hire API testers to quickly launch this tool on macOS, Microsoft Windows, and Linux.


  • It has in-built hundreds of keywords for developing test cases.
  • It can be used for exploratory and automated testing.
  • It is an all-in-one tool for web UI, API, desktop, cross-platform, and mobile testing.
  • It supports a data-driven approach, the most powerful assertion library, and AssertJ to build a fluent BDD style assertion.
  • It provides productive IDE to produce automated tests for all operating systems and platforms, regardless of the app’s complexity.
  • It has a robust recording utility that can store all UI elements to improve usability.

6. Burp Suite

It is another tool that is used by the API testing service provider, India to test the REST APIs. It is a set of tools that you can use for web application testing and penetration testing too. It comes in two editions – Profession and Community Edition. It allows integration of Postman and is extremely scalable for performing the testing of APIs and functional testing. Out-of-Band app security testing (OAST) can also be utilized with the Burp collaborator to identify the errors from the website. It helps you find the breach activity in the database with the help of a third-party.


  • It is easy to define test cases with Burp Suite and it helps test all types of defects from low to high.
  • The out-of-band application security testing (OAST) helps to remove and minimize the highest level of vulnerabilities.
  • It allows us to confirm the bugs or the bugs/errors that need to be retested through functional testing.

7. REST-assured

Anyone who is interested in the testing of REST services with Java can choose the REST-assured framework because it is an open-source platform that supports domain-specific language to make the REST service simpler.


  • It eliminates the need for writing tiresome code that may require the setting of an HTTP connection for sending a request and receiving and parsing an immediate response.
  • It provides compatibility for When/Given/Then test notation that can make your tests more human-readable.
  • REST-assured is a java library that is simple to integrate consistently, mainly when it comes to combining with a Java testing framework such as TestNG or JUnit.

8. JMeter

JMeter is one of the best open-source software to fulfill the needs of API testing services. It is a pure 100% Java application that is curated to check the load of the web application and test the functional behaviour and performance testing. Previously, it was limited to only web-based application testing. Due to the expansion of new features, it becomes now the perfect choice for load testing, functional API testing, and many other test functions.


  • It enables developers to replay test results.
  • It is used for both static and dynamic resource performance testing.
  • Its integration with Jenkins makes it possible to include API tests in the CI pipelines.


Of course, it doesn’t make any sense to depend on all tools that are mentioned in our blog. We have covered the top 8 tools for API testing for sure, but it is important to keep their benefits in mind. You also need to check-out their pricing details and analyze whether they are suitable for your project or you need something different because each person has a unique business specification that you can fulfill if you have proper knowledge of using the right tool. Before making any decision, you should carefully understand your requirements. Based on that, you can pick any one API testing tool and make an effective strategy to make your product successful.

Claire Mackerras, is a Senior QA Engineer & Editor associated with Bugraptors.  A CMMi5 certified company with extensive experience as a third party testing vendor in US and India. She is passionate about writing on technological trends for manual & automation software testing.  She likes to share her knowledge, for the readers who are interested in exploring testing tact’s and trends.