Selenium is an open-source automation framework used for testing web applications across multiple browsers and platforms. It supports languages like Java, Python, C#, and JavaScript, enabling testers to write robust automation scripts using WebDriver APIs. Selenium integrates well with tools like TestNG, JUnit, and CI/CD pipelines such as Jenkins, making it ideal for regression and cross-browser testing. Professionals seeking hands-on expertise often enroll in a Selenium Course in Chennai at FITA Academy to master framework design, scripting, and real-time project implementation.