Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Analytics is a free web analytics service that tracks and reports website traffic.
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.
Plyr is a simple, lightweight, accessible and customizable HTML5, YouTube and Vimeo media player that supports modern browsers.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
VK is a Russian online social media and social networking service.