Bootstrap was developed by Mark Otto and Jacob Thornton at Twitter as a framework to encourage consistency across internal tools. According to Twitter developer Mark Otto: “A super small group of developers and I got together to design and build a new internal tool and saw an opportunity to do something more. Through that process, we saw ourselves build something much more substantial than another internal tool. Months later, we ended up with an early version of Bootstrap as a way to document and share common design patterns and assets within the company.”[S]
Bootstrap supports responsive web design.
This means that the layout of the web pages we create adjusts dynamically, taking into account the characteristics of the device used (desktop, tablet, mobile phone).