Cowboy is a small, fast, modular HTTP server written in Erlang.
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 Sign-In is a secure authentication system that reduces the burden of login for users, by enabling them to sign in with their Google account.
Heroku is a cloud platform as a service (PaaS) supporting several programming languages.
Open Graph is a protocol that is used to integrate any web page into the social graph.