Apache is a free and open-source cross-platform web server software.
CentOS is a Linux distribution that provides a free, community-supported computing platform functionally compatible with its upstream source, Red Hat Enterprise Linux (RHEL).
Craft CMS is a content management system for building bespoke websites.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PHP is a general-purpose scripting language used for web development.
SEOmatic facilitates modern SEO best practices & implementation for Craft CMS 3.
Varnish is a reverse caching proxy.