cdnjs is a free distributed JS library delivery service.
GetResponse is an email marketing app that allows you to create a mailing list and capture data onto it.
Mailcheck is a JavaScript library designed to address the issue of misspelled email addresses during user input.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Recurly provides enterprise-class subscription billing and recurring payment management for thousands of businesses worldwide.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.
W3 Total Cache (W3TC) improves the SEO and increases website performance and reducing load times by leveraging features like content delivery network (CDN) integration and the latest best practices.