cdnjs is a free distributed JS library delivery service.
Cowboy is a small, fast, modular HTTP server written in Erlang.
Heroku is a cloud platform as a service (PaaS) supporting several programming languages.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Modernizr is a JavaScript library that detects the features available in a user's browser.