StackPath is a cloud computing and services provider.

Apache is a free and open-source cross-platform web server software.

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.

Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.

cdnjs is a free distributed JS library delivery service.

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.

Unpkg is a content delivery network for everything on npm.

BootstrapCDN is a powerful and reliable Content Delivery Network (CDN) that delivers static resources, including CSS, JavaScript, and font files, for the widely-used Bootstrap framework. By leveraging multiple server locations worldwide, BootstrapCDN accelerates website loading times, ensuring a smooth and visually appealing user experience. Additionally, it ensures website compatibility with various devices and browsers. The service reduces bandwidth usage and server load, improving web performance for developers and end-users alike.

jQuery CDN is a way to include jQuery in your website without actually downloading and keeping it your website's folder.

Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.

Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.

Fly is a platform for running full stack apps and databases.

Varnish is a reverse caching proxy.