Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
cdnjs is a free distributed JS library delivery service.
Headroom.js is a JS widget that allows you to react to the user's scroll. The header slides out of view when scrolling down and slides back in when scrolling up.
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.
LiteSpeed is a high-scalability web server.
PHP is a general-purpose scripting language used for web development.
WhatsApp Business is a free to download app available on Android and iPhone using which businesses can connect with their customers.