Security and script optimization in PHP are discussed. Much attention is paid to the description of typical programmer errors, thanks to which hackers penetrate the server, as well as methods and practical recommendations for countering external attacks are presented. Shows real-world examples of hacking Web sites and recommendations to help create more secure sites. In the 5th edition, examples have been rewritten taking into account the modern capabilities of PHP 8 and a chapter on security in the Laravel and Symfony frameworks has been added.