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Top Ten API Testing Tools


APIs are an integral part of most apps and software these days. They let different apps and programs “talk” to each other and share data. APIs facilitate the smooth running of apps and software, so it’s important to test them for performance. APIs also handle sensitive and confidential data, therefore security needs to be tested too.

API testing tools let you check the functionality of each API before you integrate them and go live with your app or software.

But with so many API testing tools out there – it can be difficult to know where to start. In this article, we’ve narrowed them down to the top ten and provided all the info you need to decide which best suits your needs.

1. TestMace

Best API Testing Tool for teams that need a simple, yet powerful tool for API testing.

Free Plan and Pricing Details: TestMace offers a basic free plan. For more advanced features, you can sign up to the Individual plan for $4 per month or a Team plan for $8 per month.

Supported API Protocols: TestMace supports a range of protocols, including REST, SOAP, and GraphQL.


  • User-friendly interface.
  • Create complex scenarios without writing any code.


  • The free plan has limited features.
  • No team collaboration features in the free Basic plan.

Unique Features of TestMace: TestMace stands out for its powerful "Node-Based" approach to create complex scenarios that don’t require coding experience. Plus, it offers a unique feature called "Flight Recorder" which captures and reproduces bugs effortlessly.

2. Tricentis Tosca

Best API Testing Tool for enterprise teams looking for full API testing capabilities with a focus on continuous testing.

Free Plan and Pricing Details: Tricentis doesn’t offer a free plan. However, it does offer a free trial. For pricing details, you need to contact the Tricentis sales team.

Supported API Protocols: Tricentis supports a wide range of protocols such as REST, SOAP, and MQTT, to name a few.


  • Extensive testing capabilities including functional, performance, and security testing.
  • Supports a broad range of protocols.


  • Could be overkill for small projects or teams.
  • Pricing details are not transparent.

Unique Features of Tricentis: Tricentis stands out with its AI-powered continuous testing platform, which provides automation assistance. It also integrates well with many popular DevOps tools, enhancing its capability for continuous testing in a DevOps environment.

3. SoapUI ReadyAPI

Best API Testing Tool for: Teams needing a beginner-friendly and modular tool for functional API testing.

Free Plan and Pricing Details: SoapUI offers a 14-day free trial on all of its three modules, with pricing as follows:

  • API Test Module – €829 per year
  • API Performance Module – €6490 per year
  • API Virtualization Module – €1221 per year

Supported API Protocols: SoapUI supports both REST and SOAP protocols.


  • Offers an easy-to-use, beginner-friendly and modular interface.
  • Extensive support for both REST and SOAP protocols.
  • Robust testing capabilities.


  • Can only code with JavaScript or Groovy.
  • Collaboration options are a little bit lacking.
  • The user interface could be more modern.

Unique Features of SoapUI: SoapUI stands out for its data-driven testing, allowing users to load data from external sources and create dynamic requests. It also offers advanced scripting capabilities for complex test scenarios.

4. Airborne

Best API Testing Tool for: Developers and testers who prefer a code-based approach to API testing.

Free Plan and Pricing Details: As an open-source tool, Airborne is free to use.

Supported API Protocols: Airborne is built for testing RESTful APIs.


  • Completely free and open-source.
  • Fully integrated with RSpec, allowing for a familiar syntax for Ruby developers.


  • It only supports RESTful APIs.
  • Requires coding knowledge.

Unique Features of Airborne: Airborne is unique in its simplicity and integration with RSpec. It supports testing for specific string patterns and JSON Schema validation.

5. JMeter

Best API Testing Tool for: Teams needing a robust performance testing tool that supports a variety of protocols.

Free Plan and Pricing Details: JMeter is an open-source tool and completely free to use.

Supported API Protocols: JMeter supports a wide variety of protocols such as HTTP/HTTPS, SOAP, FTP, JDBC, and more.


  • Extensive protocol support.
  • Strong community support due to its open-source nature.
  • Good for performance testing.


  • The user interface is not very intuitive.
  • Requires technical expertise to get the most out of it.

Unique Features of JMeter: JMeter is highly extensible and allows for custom scripting. It also supports a feature known as "sampler" which allows tests to be sent to a specific network end.

6. RapidAPI

Best API Testing Tool for: Developers seeking an all-in-one API platform with a vast directory of APIs to connect with.

Free Plan and Pricing Details: RapidAPI offers a free plan with basic features and usage limits. Premium plans start at $199/month.

Supported API Protocols: RapidAPI supports REST, SOAP, and GraphQL protocols.


  • A vast directory of APIs to connect with and test.
  • Centralized platform for managing, testing, and deploying APIs.
  • Facilitates easy team collaboration.


  • The free tier has limited usage.
  • Learning curve for first-time users.

Unique Features of RapidAPI: RapidAPI's extensive API marketplace is its standout feature, providing a single platform to find, test, and connect to thousands of APIs.

7. Postman

Best API Testing Tool for: Large teams seeking a powerful tool with plenty of customization options.

Free Plan and Pricing Details: Postman has a free trial, then a variety of pricing options starting at $12 per user/month.

Supported API Protocols: Postman supports REST, SOAP, GraphQL, and WebSockets protocols.


  • Comprehensive feature set suitable for complex tasks.
  • Wide range of integrations (e.g., Jenkins, GitHub, Slack).
  • Allows collaboration among team members.


  • May have a steep learning curve for beginners.
  • Advanced features require a paid subscription.

Unique Features of Postman: Postman stands out for its ability to manage the entire API development lifecycle, from design to testing to monitoring. It also allows teams to collaborate and share API collections.

8. Rapise

Best API Testing Tool for: Teams looking for a robust testing tool that supports both API and UI testing.

Free Plan and Pricing Details: Rapise offers a free trial but does not have a free plan. The pricing information for paid plans is available on request from the vendor.

Supported API Protocols: Rapise supports REST and SOAP protocols.


  • Supports both API and UI testing.
  • Comes with a robust set of features for automation testing.


  • The learning curve for beginners can be steep.
  • Pricing information is not readily available.

Unique Features of Rapise: Rapise has a unique hybrid object and keyword-driven testing approach that enables users to build flexible and scalable test scripts. It also supports automated testing of desktop, web, and mobile applications.

9. REST-assured

Best API Testing Tool for: Java developers seeking an open-source platform specifically designed for RESTful API testing.

Free Plan and Pricing Details: REST-assured is an open-source project, and thus it's free to use.

Supported API Protocols: REST-assured is designed specifically for testing REST protocols.


  • Specifically designed for REST API testing.
  • Supports BDD Given/When/Then syntax, making it easier to write and read tests.


  • Limited to Java, which may not suit teams using other languages.
  • Doesn't provide support for SOAP or GraphQL.

Unique Features of REST-assured: REST-assured's BDD syntax simplifies the process of writing tests, making it possible to write powerful and readable tests. It's also a straightforward tool for testing REST services in Java.

10. Katalon Studio

Best API Testing Tool for: Teams requiring a comprehensive tool that supports both API and UI testing.

Free Plan and Pricing Details: Katalon Studio has a limited free version. The premium version, with advanced features starts at $167 per month.

Supported API Protocols: Katalon Studio supports REST and SOAP protocols.


  • Offers both API and UI testing capabilities.
  • Easy to set up and use with minimal onboarding.
  • Can handle complex test scenarios.


  • The free version lacks some advanced features.
  • Some users have reported that the tool may be slow at times.

Unique Features of Katalon Studio: Katalon Studio provides an integrated environment for testers and developers to integrate and manage API tests, along with the ability to reuse test artifacts across projects.


In this post, we've reviewed the top 10 API testing tools, their key features, supported protocols, pros and cons, and pricing details. Each of these tools offers unique strengths that make them suitable for different types of users and use cases.

When choosing the right API testing tool for your needs, consider the complexity of your testing requirements, your team's technical skills, the supported protocols, and of course, your budget.

Whether you need a free and simple tool like REST-assured, a comprehensive suite like Katalon Studio, or something in-between like Postman or RapidAPI, you're sure to find a tool that fits your needs.

Always remember that the key to successful API testing is not only the tool you use but how you use it. With the right tool and approach, you can ensure your APIs are reliable, secure, and efficient, ultimately leading to a smoother, more robust software or application.

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