Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Phusion Passenger is a free web server and application server with support for Ruby, Python and Node.js.
RackCache is a quick drop-in component to enable HTTP caching for Rack-based applications.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.