Free open-source frameworks, libraries, and tools are the go-to solutions for automation testing.

The main difference between these is knowing your preference between building a brand new test automation framework using libraries or working with a made-ready tool where testing is all you will have to care about.

This article gives you a quick glance at the Top 10 Free and Open Source Testing Tools, Framework and Libraries.

Katalon Studio

Katalon Studio is a popular and free test automation tool for web, mobile, API and desktop (Windows). Offering both low-code and scripting methods, Katalon Studio removes the complicated training to build and maintain a separate testing framework.

With everything built-in, users can focus directly on testing activities and spend less effort on creating, running and maintaining tests.

Feature highlights:

Selenium

Selenium is probably the first name that pops up on the subject of web-based and open-source test automation. To be more exact, Selenium wouldn’t be considered as a tool, but an open-source library.

With the field-famous trifecta of Selenium WebDriver, Selenium IDE, Selenium Grid and the recent release of Selenium 4, this is sure to be the top choice for coding enthusiasts.

Feature highlights

Website: https://www.selenium.dev/

Appium

Sharing a similar suffix as Selenium’s, Appium is likewise the open-source framework to remember for mobile automated testing. From native, mobile web to hybrid applications, Appium is a highly sought-after option to eliminate the need for recompiling applications and automating APIs.

Feature highlights

Website: https://appium.io

Apache JMeter

Apache JMeter, or JMeter in short, is an automation tool for performance (load and stress testing) and functional testing. JMeter’s primary uses are to measure the performance of applications and act as virtual users to send requests to the designated server.

Feature highlights

Website: https://jmeter.apache.org

SOAP UI

To test SOAP and REST APIs, we got SOAP UI. Aside from API testing, SoapUI’s open-source application for web service testing additionally covers functional, load, compliance and mock testing.

Feature highlights

Website: https://www.soapui.org

Robot Framework

Using Python as the main scripting language, Robot Framework is an open-source framework for acceptance testing and robotic process automation (RPA). The Robot Framework is commonly associated with free mobile and desktop applications testing tools.

Feature highlights

Website: https://robotframework.org

Watir

Watir, or Web Application Testing in Ruby, provides you with open-source libraries in Ruby for cross-browser or web test automation. Watir uses Selenium under the hood, so it’s able to utilize Selenium’s common API.

Feature highlights

Website: https://watir.com

JUnit

Java plus unit testing give us JUnit. Ranking 7th in Java Top 10 Libraries, this free open-source testing framework is a favorite among Java developers to edit and refactor code at the unit level. What’s more, the release of JUnit 5 has brought useful updates like better organizing tests in hierarchies, simultaneous use of multiple runners at once and more.

Website: https://junit.org

Robotium

Often referred to as the “Selenium for Android,” Robotium is a popular open-source framework for Android applications black-box testing, both native and hybrid.

Website: https://github.com/RobotiumTech/robotium

Citrus

Our last open-source test automation framework is Citrus. Citrus would definitely ring a bell for developers working with integration testing and verifying messaging transport connectivity. As well as that, connecting JUnit or TestNG to use in complementary is common to script Java-based unit tests.

Website: https://citrusframework.org

Katalon Studio or Open-Source Frameworks?

In case you’ve been thinking about which is the best tool to choose – don’t.

With the cost out of the picture, it’s not a good idea to say what is best without giving the context.