cdnjs is a free distributed JS library delivery service.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Imgix is a visual media platform for managing, processing, rendering, optimising and delivering your existing images.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Polyfill is a service which accepts a request for a set of browser features and returns only the polyfills that are needed by the requesting browser.
Rewardful is a way for SaaS companies to setup affiliate and referral programs with Stripe.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.