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.
cdnjs is a free distributed JS library delivery service.
Django is a Python-based free and open-source web application framework.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Heroku is a cloud platform as a service (PaaS) supporting several programming languages.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.