Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
jQuery UI is a collection of GUI widgets, animated visual effects, and themes implemented with jQuery, Cascading Style Sheets, and HTML.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Plausible is an open-source alternative to Google Analytics.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
RequireJS is a JavaScript library and file loader which manages the dependencies between JavaScript files and in modular programming.