Bootstrap is the more common of the two in our index: it runs on 9,432 websites against 12 for Angular Material, and 5 sites use both. Counts come from real scans, not vendor claims.
Angular Material is a UI component library for Angular JS developers. Angular Material components assist in constructing attractive, consistent, and functional web pages and web applications.
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.
5 sites run both Angular Material and Bootstrap. That is 42% of the sites using Angular Material, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.