In addition to the framework, Bootstrap contains user interface components, layouts and JS tools. Source code and precompiled applications are also available. Bootstrap was created in mid-2010 by Mark Otto and Jacob Thornton at Twitter to improve the uniformity of tools used on the site and reduce maintenance costs for the site. Previous versions of the programme were referred to as Twitter Blueprint and Twitter Bootstrap.
After a few months of development, Twitter conducted its inaugural Hack Week, and the project expanded as developers of various skill levels stepped in without any external supervision from the company. As of today, it still serves as a style guide for internal tool development.
There have been almost twenty releases since the first on August 19, 2011, including two significant rewrites with v2 and 3. To make the entire framework more responsive, we included a responsive stylesheet in Bootstrap 2. By using Bootstrap 3, we made it responsive by default, with a mobile-first focus.