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.
D3 based reusable chart library
cdnjs is a free distributed JS library delivery service.
Google Maps is a web mapping service. It offers satellite imagery, aerial photography, street maps, 360° interactive panoramic views of streets, real-time traffic conditions, and route planning for traveling by foot, car, bicycle and air, or public transportation.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Intersection Observer is a browser API that provides a way to observe the visibility and position of a DOM element relative to the containing root element or viewport.
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.
JSDelivr is a free public CDN for open-source projects. It can serve web files directly from the npm registry and GitHub repositories without any configuration.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
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.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.