15+ Best API Tools For Testing API {REST & SOAP}

Want to launch flawless applications for optimum customer experience? In that case, API testing is the key. Regardless of the sector you work in, you would need to use the software apps. To ensure that the software performs seamlessly, it is important to carry out API testing. API testing helps in identifying potential defects at various layers of the software and delivering the best possible experience to users. 

It pinpoints the inconsistencies and errors in the software applications. It tests a number of components of the applications. The core aim of API testing tool is to ensure that the API used in the project meets the security, reliability, functionality, and performance requirements of the applications.

When it comes to API testing, the use of the right testing tool is vital to ensure optimum results. The API testing tools are nothing but software that enables the testers to determine whether the APIs function correctly or not. They help in identifying the potential divergence from the expected results. It allows the testers to ensure the security and reliability of the applications. 

There are two types of API testing tools available. It includes lightweight tools and enterprise tools. The lightweight API testing tools are open-source or free tools that are readily available to the testers. However, it is important to note that these tools can be used for free for a short period of time only. On the other hand, enterprise tools are more powerful tools that support the continuous testing of applications. Based on the specific requirements of your project, you can choose the best API testing tools.

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What is an API?

It’s crucial to comprehend API before delving further into the specifics of API testing tools. Application Programming Interface is referred to as API. Through a set of protocols and specifications, API, a software middleman, facilitates communication between two apps. It is an important component that facilitates interaction among software applications. There are different types of APIs, including SOAP APIs, REST APIs, Websocket APIs, and RPC APIs. 

While using an application on your smartphone, the app first connects to the internet to send data to a specific server. Then the server works on retrieving the data, interpreting it, and finally sending it back to your smartphone. The data is then interpreted by the application and presented in an easily understandable manner for the users. All of these actions happen with the help of APIs. 

How to Choose the Right API Testing Tool for You?

Considering the variety of API testing tools available, choose the best one might be a bit difficult. You must bear in mind a number of crucial considerations while choosing the appropriate instrument. Here are some of the important factors to help you decide on the right API testing tool for your project.

• Size of the Team

Not all API testing tools are ideal for every team size. So, the first thing you need to consider is the size of the team. In case you have a quite large team, you must choose an API testing tool that has a sharing option. It means that a number of users can use the tool at the same time. It can help in making teamwork easier for your testers and developers. Moreover, it can also enable you to save on costs significantly.

• Complexity

Different API testing tools have different levels of complexity in terms of use. Several tools demand specific coding knowledge in order to use them for testing API. On the other hand, there are user-friendly options that can easily be used by testers with less technical knowledge. On the basis of the skillsets of your development and testing team, you can decide on the right tool to use. If you have less skilled testers, it is always better to opt for the less complex and user-friendly API testing tools.  

• Tool Features

Features are another important factor that you must consider when choosing the API testing tools. The more features of the testing tools, the better will be the overall outcome. However, make sure that the features are not too complex to understand and use.

• API Documentation

API documentation is something you must not overlook when selecting an API testing tool for your project. Look for a tool that allows easy documentation of the API. It will help your development team to stay updated throughout the application testing and development process.

• Cost

The cost of the API testing tools will vary depending on the tool you choose and the features it offers. Make sure that the cost of the testing tool aligns perfectly with your set budget.

15 API Testing Tools to Use in 2022

1. ReadyAPI

SmartBear’s ReadyAPI is one of the popular API testing tools that allow security, load, and functional testing of SOAP, RESTful, and other web services. The intuitive platform offers the testers four powerful tools. It includes API security testing, API performance testing, API functional testing, and API and web virtualization. 

Advantages:

• ReadyAPI can be easily integrated into different environments.
• It offers end-to-end quality testing of applications.
• It has functionalities and features that allow reusing the functional tests.
• It allows the creation of data-driven and comprehensive functional API tests.

Features:

• ReadyAPI offers native support for Docker, Azure, Jenkins, Git, etc.
• It allows parallel execution of job queuing and functional tests.
• It supports Command-line and allows automated testing.
• The Smart Assertion feature of the tool allows the creation of bulk assertions against several endpoints. 

Pricing of Tool:

• $659/year for SoapUI
• $5999/year for LoadUI Pro
• $1199/year for ServiceV Pro

Total Number of Users: Up to 50 users 

Year of Release: 2022

2. Postman

When it comes to API testing tools, Postman is a popular choice among testers. This API development environment consists of three parts, namely, Workspaces, Collections, and Built-in tools. It is a comprehensive option that allows you to design, test, monitor, and document REST APIs. It is an HTTP client that enables your testers to perform both manual and automated testing. 

Advantages:

• Postman is easy to use and ideal for beginner-level testers.
• It has an intuitive user interface.
• It prevents the testers from the hassle of adopting the same languages as the developers.
• It is also ideal for experts looking for customizable solutions. 

Features:

• Postman is widely used for exploratory and automated testing.
• It allows knowledge sharing among team members.
• It supports RAM and Swagger formats. 

Pricing of Tool:

• The free version comes with limited features
• For individual teams, $12 per user/month
• For businesses, $24 per user/month

Total Number of Users Per Account: Any number of users

Year of Release: 2012

3. SoapUI

One of the top testing tools for REST and SOAP is called SoapUI. It enables testing of many API types and supports a wide variety of technologies and protocols. It helps in the quick creation and execution of automated regression, functional, and load tests. 

Advantages:

• SoapUI is easy to use and ideal for both non-technical and technical users.
• It offers drag-and-drop features for easy building of the API tests.
• It allows faster testing of the APIs. 

Features:

• SoapUI can load data from databases, Excel, and other files to stimulate the interaction of consumers with APIs.
• It supports IoT, SOAP, REST, and JMS. 
• It allows the reusability of scripts. 

Pricing of Tool:

• Free version
• $759/year.

Year of Release: 2005

4. Katalon Studio

Katalon Studio is a popular API testing tool that combines automated and manual testing and tests desktop applications, web APIs, and mobile apps. For web APIs, it can perform both SOAP and REST requests. It allows the testes of all skill levels to easily use this testing tool. 

Advantages:

• Katalon Studio allows easy deployment.
• It can combine Web/API services and UI for several environments.
• It has a library containing built-in automation keywords that help speed up the coding process. 

Features:

• Katalon Studio is ideal for exploratory and automated testing.
• It provides customizable and pre-built code templates.
• It supports CI/CD integration. 

Pricing of Tool:

• Free version
• $759/year

Total Number of Users Per Account: 1

Year of Release: 2015

5. JMeter

JMeter is an API testing tool that allows testers to test the performance and load of different applications. It enables the developers to effectively test the JDBC database connections. It works well with different protocols such as SOAP and REST. This API testing tool is ideal for use by experts. 

Advantages:

• JMeter supports various programming languages.
• It allows the testers to easily replay test results.
• It can easily adapt to the specific needs of the testers.

Features:

• JMeter can work well with CSV files.
• It allows the users to include API tests in CI pipelines. 
• It allows testing performance with the use of static and dynamic resources. 

Pricing of Tool:

• Free 

Total Number of Users: 10,000 

Year of Release: 1998

6. Eggplant

Eggplant is a popular tool used by testers in order to perform end-to-end API testing. It allows comprehensive testing of all the APIs. It is mostly utilized for performance, cross-platform, internet application, and mobile testing. The tool can help the testers identify the inconsistencies of the APIs before they affect the user experience. 

Advantages:

• Eggplant is an ideal testing tool that speeds up deployments.
• It allows early identification of potential abnormalities.
• It reduces the overall testing efforts of the testers. 

Features:

• Eggplant can build and execute different API tests easily with parameters, pre-configured snippets, and SenseTalk Scripts.
• It allows an understanding of how API behaves with invalid and valid values.
• It allows the auto-generation of different elements of test automation.

Pricing of Tool:

• NA 

Total Number of Users: NA

Year of Release: 2011 

7. Assertible

Assertible is one of the new API testing tools available to the testers. However, it has evolved as a user-friendly and robust tool for API testing. Testers can use this API testing tool to build, automate, and store tests for HTTP services and REST API. 

Advantages:

• Assertible allows quick identification of potential problems and allows faster testing.
• It can synchronize with the tests automatically, doing away with the requirement for manual updates.
• It allows simply performing effective API testing. 

Features:

• Assertible allows automating the API tests at different levels.
• It facilitates easy integration with tools like Zapier, GitHub, and Slack.
• It allows performing the API tests even after the deployment of applications. 

Pricing of Tool:

• Free version
• $25 per month
• $50 per month
• $100 per month

Total Number of Users: up to 2 users

Year of Release: NA

8. Rest Assured

Another popular API testing tool that is used to test REST services is called Rest Assured. It helps in making the REST testing quite simple and easy. It is used to verify and validate the responses to REST requests. 

Advantages:

• Rest Assured allows seamless integration with the Serenity automation framework. 
• Even if the user is not an HTTP expert, they can use this testing tool.
• The tool’s built-in features save users from having to start from scratch while creating code. 

Features:

• Rest Assured comes with a number of authentication mechanisms. 
• It supports PATCH, PUT, HEAD, DELETE, and POST requests.
• It supports the BDD When/Given/Then syntax. 

Pricing of Tool:

• Free

Total Number of Users: NA

Year of Release: 2019

9. Karate DSL

Karate DSL allows the users to easily create scenarios for API-based BDD tests. Without having to invest time in writing down the step definitions, it allows the testers to carry out the API tests faster. It is specifically designed for facilitating automated API testing. 

Advantages:

• Karate DSL does not require any programming language.
• It provides easy-to-write tests to the users.
• It allows the testers to write the tests in any language supporting XML, HTTP, and JSON.

Features:

• Karate DSL comes with strong assertion capabilities.
• It supports the testing and generation of reports.
• It allows configuration staging and switching. 

Pricing of Tool:

• Free

Total Number of Users: NA

Year of Release: 2019

10. Swagger

Swagger is one of the best api tools that is used by testers for API designing. It allows you to easily test the security, performance, and functionality of the applications. When used along with the ReadyAPI platform, it allows you to create, execute, and manage API tests much faster. 

Advantages:

• Swagger supports all types of services, including SOAP, REST, and GraphQL.
• It allows closely adhering to protocols.
• It offers effective API documentation. 

Features:

• Swagger allows importing user API definitions for validating schema rules.
• It enables the automatic generation of assertions.
• Swagger Inspector allows the testers to easily inspect API response requests to ensure proper functionality. 

Pricing of Tool:

• Free version
• $30 per month 

Total Number of Users: More than 25 users 

Year of Release: 2011

11. API Fortress

API Fortress is an ideal API testing tool for functional and performance testing. It allows you to easily build, execute, and automate the tests. It also serves as a powerful monitoring tool for REST and SOAP. 

Advantages:

• API Fortress improves transparency and reduces redundancy.
• It is compatible with the cloud and physical hardware.
• It is ideal for novice users with less technical knowledge. 

Features:

• The monitoring capabilities of the tool allow keeping a close eye on the APIs.
• The reporting dashboard of API Fortress consolidates results to provide a comprehensive view. 
• It is capable of running unlimited tests and offers alerts when any issue is detected. 

Pricing of Tools:

• Free
• $1500 per year
• $500 per year  

Total Number of Users: NA

Year of Release: 2014

12. Tricentis Tosca

Tricentis Tosca is a tool that allows continuous testing of applications. It allows the testers to test the APIs at different stages of the development cycle. Irrespective of the environment and build of your API, this testing tool can perfectly suit your application. 

Advantages:

• Tricentis Tosca allows script-free and no-code end-to-end test automation.
• It enables the testers to easily achieve long-term automation.
• It can significantly reduce the number of manual tests required. 

Features:

• Tricentis Tosca simplified script maintenance and maximized reuse.
• It allows the completion of regression tests in an efficient manner.
• API tests can be performed across packaged apps and cross-browsers. 

Pricing of Tools:

• $11,000 per year 

Total Number of Users: NA

Year of Release: 2006

13. Apigee

Apigee can be your best choice if you’re seeking an API testing solution that runs in the cloud. The employment of several editors enables consumers to utilise its advantageous features. It helps in testing and monitoring the API performance. 

Advantages:

• Apigee offers a customizable development portal.
• It can handle APIs with a huge amount of data. 

Features:

• Apigee supports Node.js.
• It identified performance issues by tracking API traffic, error rates, and response times.
• It allows the creation of API proxies. 

Pricing of Tools:

• Free
• $500 per month
• $2500 per month

Total Number of Users: NA

Year of Release: 2020 

14. Airborne

Airborne is another API testing tool that does not have a UI. It offers text files to the testers in order to write codes. 

Advantages:

• Airborne is an open-source API testing tool.
• It is ideal for Rest API testing.
• To use the tool, you just have to remember a few key methods. 

Features:

• Airborne works well with Rack applications.
• It works well with APIs written in Rails. 

Pricing of Tool:

• Free

Total Number of Users: NA

Year of Release: NA 

15. Hoppscotch

Hoppscotch is a lightweight API testing tool that comes with a minimalistic UI. It provides a complete set of functionalities to the testers to ensure easy testing of the APIs. 

Advantages:

• Hoppscotch allows the users to gain access to the history of previous requests. 
• It allows streaming server-sent events. 

Features:

• Hoppscotch provides a full-duplex communication channel.
• It allows the sending and receiving of data with the use of the SocketIO server. 

Pricing of Tool:

• Free

Total Number of Users: NA

Year of Release: 2015

Conclusion

API testing tools have become essential to identify errors earlier in the development stage. On the basis of your unique requirements, make sure to choose the best API testing tool for your project. 

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