Apache is a free and open-source cross-platform web server software.
cdnjs is a free distributed JS library delivery service.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
MODX (originally MODx) is an open source content management system and web application framework for publishing content on the World Wide Web and intranets.
PHP is a general-purpose scripting language used for web development.
Stellar.js is a JavaScript library and jQuery plugin specifically designed to deliver parallax scrolling effects for web pages.