Top Free Open-Source Testing Tools and Frameworks

Does your team have the resources to build a test automation framework from the ground up with open-source libraries? Or is a pre-built and comprehensive testing tool more preferable to speed up your software development test cycle (STLC)?

Knowing which suits your scenario most will make the tool selection process much more accurate, along with this list of the top 10 free and open-source testing tools, frameworks, and libraries.

Katalon Studio

If the responsibility of quality assurance has already started stacking up, then Katalon Studio would surely be a great choice. Katalon Studio is designed with a single mission in mind – making the web, mobile, API, and desktop (Windows) test automation free and effortless. 

You can expect to cycle through every step in weeks instead of months by applying low-code methods for test design, execution, maintenance, and reporting.

Top Features

• Compatible with Windows, macOS, and Linux
• Record and Playback, Manual and Script Mode (Java and Groovy supported) for flexible and fast test creation
• Built-in parallel testing, Terminate Execution Conditionally, Self-Healing, SmartWait and Failed Test Retry for smarter execution
• Easily reuse test artifacts across projects and maintain tests with Object Refactoring and the Page Object Model design
• Test reports can be stored, centralized, and exported into HTML, PDF, and CSV
• Supports Cross-Browser Testing (Headless, Chrome, Edge, Firefox, and Safari) and Cross-Platform Mobile Testing (iOS, Android)
• Allow projects from Selenium, SoapUI, and Postman to be imported
• No workarounds to connect CI/CD systems (Jenkins, Bamboo, Azure DevOps, CircleCI, etc.) and ALMs (e.g., Jira)
• Video tutorials and official documentation

Download Katalon Studio for Free

Selenium

With the Selenium WebDriver, Selenium IDE, Selenium Grid, and the latest release of Selenium 4, this is certainly the free open-source library for coding enthusiasts.

Top Features

• Supports Java, JavaScript (Node.js), Groovy, Scala, PHP, Perl, Python, Ruby, or C#
• Test scripted on Eclipse, Visual Studio or NetBeans can be imported
• Works on macOS, Windows, and Linux
• Add-ons and plugins can be personalized 
• Can integrate with Ant, Maven, TestNG, JUnit, NUnit, etc.

Website: https://www.selenium.dev/ 

Appium

Appium is similar to Selenium’s free open-source framework, but for mobile automated testing on native, mobile web, and hybrid applications.

Top Features

• Supports whichever programming language Selenium has with the JSON Wire Protocol ( Java, PHP, Objective-C, C#, Clojure, JavaScript with Node.js, Python, Perl or C#)
• Execute on iOS and Android platforms
• No source code is needed to test mobile application

Website: https://appium.io   

Apache Meter

For performance (load testing & stress testing) and functional testing, Apache Meter (Jmeter) would be a very popular choice. 

Top Features

• Supported programming language: Java
• Custom code with BeanShell processor
• Easy-to-use UI/GUI 
• Can test protocols such as HTTP, HTTPS, JDBC, LDAP, FTP, LDAP, SOAP, POP3, IMAP, SMTP, TCP, and Java-scripted protocols. Other applications and servers can be found on https://jmeter.apache.org/ 
• Third-party reporting or CI/CD tools (e.g., Jenkins) can be integrated  

Website: https://jmeter.apache.org

SoapUI

REST and SOAP-based web service technologies require an entry point for validation. Conveniently, that’s what SoapUI was made for. Other testing spectrums such as functional, security, load, and mocking are also commonly used with SoapUI.

Top Features

• Supported programming languages: Groovy and Javascript
• Workable with SOAP/WSDL, REST, and JMS protocols 
• Enable Data-Driven Testing (DDT) with DataSource TestStep to test against Excel/CSV files and databases
• Create automated tests using drag-and-drop or UI interactions (point-and-click)
• Can import scripts are written with Maven, HUDSON, JUnit, and Apache Ant
• Export test reports in the HTML format

Website: https://www.soapui.org 

Robot Framework

As a Python-based framework, the open-source libraries provided by Robot Framework, are free and used to perform acceptance testing and robotic process automation (RPA).

Top Features

• Open to working with programming languages such as Python, Jython (Java), PyPy, and IronPython (.NET)
• Compatible with Windows, macOS, Unix, and Linux
• Scripts written with Eclipse, RIDE (Robot Framework IDE), or text editors can be imported
• Content-assist utilities like autocomplete completion or syntax highlighting to speed up scripting/coding
• Can be connected to Appium and Selenium

Website: https://robotframework.org 

Watir

Watir is a large open-source library to write web browser or cross-browser automation test scripts in Ruby. Using Selenium under the hood, any W3C specifications will remain compatible and Watir is able to inherit the more common API.  

Top Features

• Script easy-to-read tests
• Make reusable libraries by code structuring and exporting XML
• Supported browsers: Chrome, Firefox, Edge, Internet Explorer, Safari, and Headless
• Cucumber and RSpec integration for BDD testing

Website: https://watir.com 

JUnit

Taking the 7th position in Java Top 10 Libraries, JUnit is a popular unit testing framework for Java-based developers.

Top Features

• Supports scripting and running tests right from common IDEs and build tools (e.g., IntelliJ IDEA, Eclipse, NetBeans, Gradle, and Maven)
• Uses assertions and annotations for users to write well-structured and reusable tests
• Can be combined with Selenium to assist cross-browser testing

Website: https://junit.org 

Robotium

To test Android applications, Robotium is frequently seen as the open-source “Selenium for Android.” 

Top Features

• Programming language: Java
• Integrates with IDEs (e.g., Gradle, Maven, and Ant) 
• Runtime binding
• Config.sleepDuration and Config.sleepMiniDuration to alter execution speed

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

Citrus

Citrus exists to automate integration testing. It’s also normally paired with JUnit and TestNG to combine integration and unit testing efforts. 

Top Features

• Tests messaging protocols and data formats (HTTP, REST, SOAP, Kafka, JMS, XML, JSON, etc.)
• Scripting using Java or XML
• Integrates with Apache Camel, Arquillian, Kubernetes, and Docker for microservice environment integration testing 
• Can be used with Selenium for front-end functionality testing

Website: https://citrusframework.org/

That's all! If you have any more suggestions, feel free to share them in the comments below.