Tampermonkey is a popular browser extension that allows users to run custom scripts on websites. These scripts, known as userscripts, can modify the appearance and functionality of web pages, enhancing the user experience. It is available for various browsers, including Google Chrome, Firefox, and Microsoft Edge. With Tampermonkey, users can easily manage their scripts, enabling or disabling them as needed. The extension also provides a built-in editor for creating and editing scripts, making it accessible for both beginners and experienced developers. Overall, Tampermonkey empowers users to personalize their web browsing experience.