Apache is a free and open-source cross-platform web server software.
Braintree, a division of PayPal, specializes in mobile and web payment systems for ecommerce companies. Braintree provides clients with a merchant account and a payment gateway.
cdnjs is a free distributed JS library delivery service.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
jQuery UI is a collection of GUI widgets, animated visual effects, and themes implemented with jQuery, Cascading Style Sheets, and HTML.
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.
OpenSSL is a software library for applications that secure communications over computer networks against eavesdropping or need to identify the party at the other end.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.