Bootstrap is a popular open-source front-end framework that is used to create responsive and mobile-first websites and web applications.

It provides a collection of CSS and JavaScript components, such as grids, forms, buttons, navigation bars, and more, which can be easily implemented and customized to create responsive and visually appealing web interfaces.

With Bootstrap, developers can save time and effort by utilizing pre-designed components, as well as the grid system for creating responsive layouts. It also provides numerous styling options and utilities to enhance the overall appearance and functionality of websites. Bootstrap is widely used by web developers to streamline the web development process and create consistent and visually appealing user interfaces.