What is Selenium ? and its Role. Selenium is an open-source tool that is used for automating the tests carried out on web browsers In easy terminology .. It is used for testing projects and Selenium is still considered as the first choice for many testing projects. Only testing of web applications is possible with Selenium. We can neither test any desktop (software) application nor test any mobile application using Selenium. Using Selenium You can use multiple programming languages like Java, C#, Python etc to create Selenium Test Scripts. It supports various browsers like Chrome, Mozilla, Firefox, Safari, and IE, and you can very easily automate browser testing across these browsers using Selenium WebDriver. How to Start? Before learning the concepts of Selenium, you should have a basic understanding of Java or any other object-oriented programming language. Languages supported by Selenium include C#, Java, Perl, PHP, Python and Ruby. Currently, Selenium Webdriver is most popular with Java and C#. Hope You are satisfied with the answer.