cdnjs is a free distributed JS library delivery service.
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.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
Plyr is a simple, lightweight, accessible and customizable HTML5, YouTube and Vimeo media player that supports modern browsers.
Simple Analytics is a privacy-friendly Google Analytics alternative.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.