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.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
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.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.