NAXSI (Nginx Anti XSS & SQL Injection) is a third-party nginx module designed to prevent common web application attacks. The module operates by reading a small subset of simple, readable rules that contain patterns associated with website vulnerabilities. These rules identify and block malicious input patterns commonly used in web attacks. NAXSI functions as a web application firewall by filtering HTTP requests and responses based on predefined security rules. The module examines incoming traffic for suspicious patterns and blocks requests that match known attack signatures. The tool comes with default rules that cover a significant portion of known vulnerability patterns. For example, it restricts characters like '<', '|', and keywords like 'drop' that are commonly used in XSS and SQL injection attacks. NAXSI is available as a package for many UNIX-like platforms and integrates directly with nginx web servers. The module provides real-time protection against web application attacks without requiring significant configuration changes to existing nginx deployments.