Rexsser is a Burp Suite plugin that automates the detection of reflected Cross-Site Scripting (XSS) vulnerabilities in web applications. The plugin operates by extracting keywords from HTTP responses using regular expressions and then testing these keywords for reflected XSS within the defined target scope. It integrates directly with Burp Suite's workflow, allowing security researchers and developers to identify potential XSS vulnerabilities during web application testing. The tool focuses on reflected XSS detection by analyzing response content and testing for reflection patterns that could indicate security weaknesses. Rexsser is distributed as an open-source project available through GitHub, making it accessible for security testing and vulnerability assessment activities.