 
            A web application firewall (WAF) is essential for protecting online applications from threats like data theft, code execution, and server compromise. Unlike traditional network firewalls, a WAF focuses on securing HTTP traffic. Safeline, a popular self-hosted WAF, uses machine learning to intelligently filter traffic, achieving high accuracy and low false positives. It defends against various threats, including SQL injection, cross-site scripting, and brute force attacks, and offers features like rate limiting, bot defense, content protection, and access control. Safeline is designed for simplicity, with intuitive configuration and open-source roots, making it accessible for both small projects and large enterprises.