Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Google Optimize allows you to test variants of web pages and see how they perform.
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.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.