Bootstrap was created at Twitter in mid-2010 by Mark Otto and Jacob Thornton. Prior to being an open-sourced framework, Bootstrap was known as Twitter Blueprint. A few months into development, Twitter held its first Hack Week and the project exploded as developers of all skill levels jumped in without any external guidance. It served as the style guide for internal tools development at the company for over a year before its public release, and continues to do so today.
Anybody with just basic knowledge of HTML and CSS can start using Bootstrap.
Bootstrap's responsive CSS adjusts to phones, tablets, and desktops.
In Bootstrap 3, mobile-first styles are part of the core framework.
Bootstrap is compatible with all modern browsers (Chrome, Firefox, Internet Explorer, Edge, Safari, and Opera).