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.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
YUI is a JavaScript and CSS library with more than 30 unique components including low-level DOM utilities and high-level user-interface widgets.