Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
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.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.