11 Best Tools to Test and Build API Faster

Build API like a pro in no time.

Organizations are changing to the Microservices Architecture model to succeed in their software application projects why because most of the microservices projects use API’s (Application Programming Interfaces). Here we need to applaudbecause it has various advanced features than other models.

Like these have discrete data stores with separate commands to handle each data store; also, it allows software providers to deploy components more swiftly. And if one application is updated, the remaining applications need not be updated; they can continue their functionality.

We are in a time to provide fast results or services to end-users who use applications for their requirement. A lot of API’s are using REST services via HTTP to send and receive data. Many software testers are automating their testing with UI based test and API Tests. While comparing API Testing with UI based testing, API tests are much speedy and reliable than UI based tests.

What is API testing?

Before we step into that, I’ll let you know what API is.

In general terms, it acts as a messenger for the applications, devices, and databases. Assume you are searching for a flight through an online travel booking site. It will ask you to enter the required details like source, destination, and one trip or round trip journey details within your set prices.

Once you click on search here, API’s comes into the picture; it will interact with each airways API and which provides results meet your norms. It all just happens within seconds.

If when API doesn’t work correctly in real-time scenarios, there is no use of utilizing API, right?

To keep away from these situations, we need to opt for API testing. So before the audience using the service, we must test API. It plays a vital role in application development.

Necessary API testing is a kind of software testing to be done to develop APIs to accomplish the built application’s functionality, execution, security, and trustworthiness. It predominantly focuses on the Business Layer of software architecture. Testing is a crucial portion of succeeding in the Continuous Integration &application’s operations.

Let’s check out the following tools to ease our development tasks.


is a prominent API testing tool to test web services.

It can be able to check both SOAP Web services as well as RESTful Web Services. SoapUI is available as an open-source and PRO version, but as you can guess, the PRO version got additional functionality. It is based on Java, so it works on the majority of the operating systems; foremost, it’s easy to learn & use and reliable for all.

Trusted by millions of users, you can use them for various test cases.

  • Functional
  • Data-driven
  • Mocking
  • Security
  • Performance

You may be interested in learning in-depth, check out this.

Katalon Studio

is an automation testing tool for Web, API, and Mobile. It was rewarded as an emerging testing tool and best in the automation area.

Key features:

  • End-to-end testing solution for testers and developers
  • Supports all kind of SOAP, REST requests
  • Works with a framework such as BDD Cucumber. It’s a testing approach in which the written test cases are in natural languages helps the conveyance between business stakeholders and technical human resources.
  • Built-in integrations with Jenkins, JIRA, Slack, Docker, and qTest
  • Efficiently utilize Katalon UI/UX features like searching, drag & drop, built-in keywords, selecting test cases.

You can get it started in free with Katalon.


is inspired from JUnit and NUnit for Java language. The main motto of this is to provide easy to use functionalities and fulfill all types of testing phases like unit, integration, functional, etc.

  • By using TestNG with Selenium, you can create a prompt report where we can get to know how many test cases were unsuccessful, progressed, and bounced.
  • Easily integrate with DevOps tools such as Maven, Jenkins, Docker, etc.
  • Using Annotations in TestNG can improve easy to understand the code, and exceptions were caught automatically than JUnit.

You can create data-driven tests using TestNG.


is a kind of tool it can perform both building and testing API. It is open-source and easy to install. Postman workspace has its features like new, import, runner, my workspace, invite, collections, request tab, HTTP request, and save, etc.


  • Write and run tests for every request using JavaScript
  • While testing API in Postman, you can choose required HTTP methods like GET, PUT, POST, etc.
  • You can use Manage Environments features from Postman to give the input value from any API result.
  • Store associated endpoints into a collection.

There are a lot more advantages in postman to build API faster. Check out thisif interested in hands-on.


, it’s AKA’s best API Tools to design, build, and test APIs. Swagger tools are both open source and pro, and it has helped millions of developers & testers to deliver great API.


  • Inspector is easy to design, document, and test API
  • You can also test APIs on the cloud
  • Support all types of services like REST, SOAP
  • SwaggerHub is the platform where you can design and document with OpenAPI


is a simple yet powerful tool for automated testing. You can perform performance testing of RESTFul services with the use of JMeter scripting, and It can use different languages like Java, JavaScript, and PHP. It is designed to test web applications, but later on, it has expanded to other test functions.


  • JMeter has denoted as fast API Testing tool as it performs scope tests rapidly
  • Open-source and supports to install plenty of plugins & extensions
  • JMeter has a separate feature called adding parameters in the parameter tab that we don’t find in other programs
  • Can perform perfect functional and load testing in JMeter

Rest Assured

library is a tailor-made API tool for Java domain using people to test and validate REST Services. It is also used to test HTTP, JSON, and XML based web services, and it gives us a lot of key features like XPath validation, JSON Path syntax, easy file uploads, and specification reuse. And also, it was mainly influenced by dynamic languages suchlike Groovy, Ruby.

One of the excellent features that Rest Assured offers is you don’t need to parse XML or JSON responses after you gain the answer.

Tricentis Tosca

Tricentisis a customized continuous testing tool for DevOps platforms, as some of the leading tools had failed to meet in DevOps environments. A beginner also can understand the Tosca tool and can instantly create advanced API tests from a business perspective and then integrate them into throughout all scenarios.

Tricentis Tosca is suitable for continuous testing & automation test for mobile-based, web-based, UI, SAP, etc.


is a complete API platform where we can design, build, develop, and document API. It provides a framework to develop, test, and implement production-ready API faster. In general, to create an API, we need to define a schema for input and the output, whereas in Apiary API can be designed with input and output as mocked.

This mocked API will meet application specifications without changing any coding, while data can be integrated and tested. Building API has different stages of the workflow. Nonetheless, the apiary can provide each stage of the team to work independently.

MuleSoft API

, aka AnyPoint API Manager, is a platform where dev
elopers can build, design, manage, and publish APIs. It offers organizations to integrate with popular cloud services such as Salesforce, SAP, and many more. The AnyPoint platform uses Mule as a run time engine.

API Manager assures each API is secure and, in simple terms, is full lifecycle API management.


by Google Cloud enables API managers to design, secure, publish, analyze, monitor, and monetize APIs. It can be operated in a hybrid-cloud environment to perform digital acceleration. Apigee makes regular developers into an API Expert.

Apigee edge creates API proxies, and using these, you can get real analytics data. Proxies created by Apigee edge manages security and authentication to give better services.


Regardless, there would be the same functionality accessible in all API tools, but the approach differs. The best way to experience them is to give a try to see what works best for your business requirement.

Next, check outand.