Apache Traffic Server is an open-source caching and proxying server that serves as an HTTP/1.1 and HTTP/2 reverse proxy with caching capabilities, load balancing, request routing, SSL termination, and support for advanced HTTP features.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
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.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.