cdnjs is a free distributed JS library delivery service.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Google Optimize allows you to test variants of web pages and see how they perform.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
SweetAlert is a JavaScript library that provides alternative alert and modal dialog boxes for web applications, with customisable features, aiming to improve the user interface of the default browser dialogs.
Reveal CSS animation as you scroll down a page.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.