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Top 5 API Testing Tools: Review and Comparison For the Year 2021

In recent years, APIs have become one of the most significant trends in the transformation of organizations into truly digital enterprises. Therefore, it’s no wonder that more and more companies who aim to unify software development and testing, tend to favor API Testing.


The rise of APIs also has been met by the rise in tools for testing, managing them. While new tools emerge and others go out of demands day by day, here are some helpful reviews and comparisons to help speed up the process of choosing a right API testing solution. Let’s get an insight on the highlighted tools!

API testing tools


Being originally a Chrome browser plugin, Postman now extends their solution with the native version for both Mac and Windows.

Postman is a good choice for API testing for those who don’t want to deal with coding in an integrated development environment using the same language as the developers.

  • Easy-to-use REST client
  • Rich interface which makes it easy to use
  • Can be used for both automated and exploratory testing
  • Can be run on Mac, Windows, Linux & Chrome Apps
  • Has a bunch of integrations like support for Swagger & RAML formats
  • Has Run, Test, Document and Monitoring Features
  • Doesn’t require learning a new language
  • Enable users to easily share the knowledge with the team as they can package up all the requests and expected responses, then send to their colleagues.

Website: https://www.getpostman.com/

Pricing: Free – $21/user/month


JMeter (open source) is widely used for functional API testing although it is actually created for load testing.

  • Supports replaying of test results
  • Automatically work with CSV files, allowing the team to create unique parameter values for the API tests quickly.
  • Users can include the API tests in CI pipelines thank to the integration between JMeter and Jenkins
  • It can be used for both static as well as dynamic resources performance testing

Website: https://jmeter.apache.org/

Pricing: Open source

Katalon Studio

Katalon Studio is a free automation test tool provide a common environment to create and execute UI functional, API/Web services and mobile testing.

The capability to combine UI and Business levels (API/Web services) for different environments (Windows, Mac OS, Linux) has been considered an advantage of Katalon Studio.

Katalon Studio supports SOAP and RESTful request with various types of commands (GET, POST, PUT, DELETE) with parameterized capability.

  • Highlights:
  • Support combination test between UI and API verification.
  • Support testing both SOAP and RESTful requests.
  • Hundreds of built-in keywords for creating test cases.
  • Support one of the most powerful assertion library, AssertJ to create fluent assertion with BDD style.
  • Support data-driven approach.
  • Can be used for both automated and exploratory testing.
  • Suitable for both pros and non-techies

Website: https://www.katalon.com

Pricing: Free

Tricentis Tosca

Tricentis Tosca is a continuous testing platform for Agile and DevOps. Benefits of Tricentis Tosca include:

  • Supports many arrays of protocols: HTTP(s) JMS, AMQP, Rabbit MQ, TIBCO EMS, SOAP, REST, IBM MQ,NET TCP
  • Integrates into the Agile and DevOps Cycle
  • Maximize reuse and maintainability with model-based test automation
  • API tests can be used across mobile, cross-browser, packaged apps, etc…
  • Achieve sustainable automation with new technology
  • Reduce the time of regression testing

Website: https://www.tricentis.com/

Pricing: Contact Sales


Apigee is a cross-cloud API testing tool, allowing users to measure and test API performance, supports and build API using other editors like Swagger.

  • It is multi-step and powered by Javascript
  • Allows the design monitor, deploy, and scale APIs
  • Identify performance issues by tracking API traffic, error rates, and response times
  • Easily create API proxies from the Open API Specification and deploy them in the cloud
  • Cloud, on-premise, or hybrid deployment model on a single code base
  • PCI, HIPAA, SOC2, and PII for apps and APIs
  • Apigee is purpose-built for digital business, and the data-rich mobile-driven APIs and apps that power it.

Website: https://apigee.com/api-management/

Pricing: Free trial – $2,500/month

What are yours?

Above is the list of both open-source and commercial tools which help QA engineer from entry to expert level to ease the job of testing APIs. There are many other API testing tools available out there, each of them is perfect in certain areas and struggle in others. View full list of API Testing Tools for 2018

Hence, the testing team needs to define their particular demand before diving into finding a tool.  For example, with CI integration, ability to perform a single test quickly, and collecting statistics about performance are more important than others.

Overall, there is no perfect tool for all areas, but these are the top five highlighted tools. If your favorite tool is missed, please feel free to share your suggestion below.

3 thoughts on “Top 5 API Testing Tools: Review and Comparison For the Year 2021”

  1. Pingback: Testing Bits – June 3rd – June 9th, 2018 | Testing Curator Blog

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