Definition
Apache (formally the Apache HTTP Server) is a free, open-source web server first released in 1995 that helped establish the early web and still ships as the default on most shared-hosting plans. It serves static files directly and hands dynamic requests to PHP and other languages through modules such as mod_php or PHP-FPM, using one of several worker models (prefork, worker, event) to handle concurrent connections. Its defining feature is per-directory configuration through .htaccess files, letting each hosting account override URL rewriting, redirects and access rules without touching the global httpd.conf, a genuine advantage on shared servers where users cannot edit core config. NGINX has overtaken Apache for high-traffic and reverse-proxy workloads thanks to its event-driven architecture, though a common production stack still runs NGINX in front with Apache handling application logic behind it. Apache's module ecosystem, cPanel integration and .htaccess support keep it the practical default on shared and small VPS hosting.
How it works
Apache uses a worker-per-request model (prefork, worker or event MPMs) and loads modules for PHP, SSL, URL rewriting, authentication and more. It reads a global httpd.conf plus per-directory .htaccess files. mod_rewrite is the engine behind WordPress permalinks and similar URL handling.
Why it matters
For shared hosting and WordPress sites, Apache's .htaccess support is the reason it survives. For high-traffic sites and reverse-proxy roles, NGINX is now the better default. A common stack is NGINX in front, Apache behind it, getting the best of both.