Dragan Rapić, a contributor to Level Up Coding, highlights the importance of writing secure PHP code to protect websites and applications from cyber threats. In his article, Rapić outlines critical security practices such as validating user input, using prepared statements, and implementing robust session handling. He emphasizes the need for regular updates to PHP and dependencies, and the potential benefits of utilizing a Web Application Firewall (WAF). By adhering to these guidelines, developers can significantly mitigate the risk of malicious attacks such as Cross-Site Scripting (XSS).