Bootstrap is use to create responsive, mobile-first websites. Bootstrap is the most popular front-end component library. Bootstrap is an open source toolkit for developing with HTML, CSS, and JS.
Bootstrap, originally named Twitter Blueprint, was developed by Mark Otto and Jacob Thornton at Twitter as a framework to encourage consistency across internal tools.
After a few months of development by a small group, many developers at Twitter began to contribute to the project. It was renamed from Twitter Blueprint to Bootstrap, and released as an open source project on August 19, 2011. It has continued to be maintained by Mark Otto, Jacob Thornton, and a small group of core developers, as well as a large community of contributors.
On January 31, 2012, Bootstrap 2 was released, which added a twelve-column responsive grid layout system, inbuilt support for Glyphicons, as well as changes to many of the existing components.
On August 19, 2013, Bootstrap 3 was released, which redesigned components to use flat design, and a mobile first approach.
On October 29, 2014, Mark Otto announced that Bootstrap 4 was in development.
The first alpha version of Bootstrap 4 was released on August 19, 2015.
The first beta version was released on 10 August 2017.
The stable version of Bootstrap 4 was released on January 18, 2018 basically improving print styles and border utilities and also providing more control over the flexbox.