Selenium is a free, open-source tool that is used for automating the tests carried out on web browsers. The creation of Selenium Test Scripts requires the usage of multiple programming languages including, Java, C#, Python. Testing done with the help of the Selenium testing tool is referred to as Selenium Testing. While the Selenium software is a suite of software rather than a single tool, each piece caters to different QA testing needs of an organization. Here is the list of tools:Selenium Integrated Development Environment (IDE)Selenium Remote Control (RC)WebDriverSelenium GridYou can check out further details in this article - What is Selenium.