Calendly is an app for scheduling appointments, meetings, and events.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
A modest JavaScript framework for the HTML you already have.