Introduction to PHP

Rasmus Lerdorf began PHP in 1994; it evolved into a general-purpose language maintained by a large open-source community. PHP commonly runs behind Apache or Nginx through PHP-FPM, executes one request, and returns HTML, JSON, files, or redirects.

Practical example

<?php
declare(strict_types=1);
$name = 'PHP';
echo "Hello, $name!";

PHP supports dynamic values, modern type declarations, OOP, exceptions, streams, database extensions, and Composer packages. Request-local memory is temporary; durable state belongs in databases, sessions, caches, queues, or files. Server-side execution hides source but does not make input, SQL, output, or secrets safe.