Selenium

Selenium is the leading open-source web browser automation framework used by QA engineers and developers to write automated tests that control real browsers (Chrome, Firefox, Safari, Edge) for web application testing. Originally developed by Jason Huggins at ThoughtWorks in 2004 and donated to the Apache Software Foundation before becoming an independent project under the Software Freedom Conservancy, Selenium is maintained by a global volunteer community and is the foundation of virtually every major web test automation stack. The Selenium project includes WebDriver (the W3C standard API), Grid (distributed test execution), and IDE (record-and-playback tool).\n\nSelenium WebDriver provides a programmatic API (available in Java, Python, JavaScript, C#, Ruby, and other languages) that drives real browsers using the native browser automation protocol — controlling browser navigation, clicking elements, filling forms, and asserting page states. Selenium Grid enables distributing test execution across multiple machines and browsers simultaneously, dramatically reducing test suite run time for large projects. Major test frameworks (TestNG, JUnit, pytest, Mocha) integrate with Selenium as the browser driver layer.\n\nIn 2025, Selenium remains the most widely used web test automation framework despite newer alternatives — Playwright (Microsoft) and Cypress have gained significant adoption among modern web development teams for their superior developer experience and faster execution in CI environments. Selenium's advantage is its maturity, language support breadth, and existing enterprise adoption at scale. The Selenium 4 release introduced native W3C WebDriver Protocol support, BiDirectional API (CDP-like capabilities), and improved grid. The project's 2025 direction focuses on BiDi protocol capabilities that match Playwright's modern features while maintaining the broad browser and language compatibility that makes Selenium the enterprise automation standard.