Undoubtedly the most popular HTML, CSS and JavaScript framework for developing responsive, mobile first projects on the web.
Bootstrap is a mobile-first front-end framework for Web development. It is the most-popular project on GitHub by far. Originally created by Twitter as a framework for the Twitter GUI, Bootstrap was first released on 19-08-2011.
Bootstrap, originally named Twitter Blueprint, was developed by Mark Otto and Jacob Thornton at Twitter as a framework to encourage consistency across internal tools. Before Bootstrap, various libraries were used for interface development, which led to inconsistencies and a high maintenance burden.
On January 31, 2012, Bootstrap 2 was released, which added built-in support for Glyphicons.
Version 3 of Bootstrap was launched on 19-08-2013, featuring a new design with an optional theme, a mobile-first perspective, a new customizer, and more responsive models.
It's been a crazy long ride to say the least and we're stoked to finally have this out in the wild"
Mark Otto, Jacob Thornton, and team wrote in Version 3's official launch post on the Bootstrap Blog.
Mark Otto announced Bootstrap 4 on October 29, 2014. The first alpha version of Bootstrap 4 was released on August 19, 2015. The first beta version was released on 10 August 2017. Mark suspended work on Bootstrap 3 on September 6, 2016, to free up time to work on Bootstrap 4.
Bootstrap 4 was finalized on January 18, 2018.