Bootstrap is described as 'Open-source collection of tools for creating browser sites and applications. It contains HTML and CSS-based design templates for typography, forms, buttons, charts, navigation and other interface components, as well as optional JavaScript extensions' and is a very popular CSS Framework in the development category. There are more than 100 alternatives to Bootstrap for a variety of platforms, including Web-based, Self-Hosted, Mac, Windows and Linux apps. The best Bootstrap alternative is Materialize, which is both free and Open Source. Other great apps like Bootstrap are Foundation, Bulma, Semantic UI and Tailwind CSS.