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.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Mailchimp is a marketing automation platform and email marketing service.