An AntiSamy developer works with the AntiSamy library, a tool that helps to protect websites from Cross-site Scripting (XSS) and other code injection attacks. Their role involves implementing and configuring this library to sanitize user inputs, ensuring they can't inject harmful scripts into web applications. They also maintain and update the AntiSamy policy file, which defines what HTML tags, CSS properties, and JavaScript events are allowed. Additionally, they may collaborate with other developers to ensure the secure handling of user-supplied data, debug issues related to input sanitization, and contribute to improving the AntiSamy tool itself.