Bootstrap is an open-source toolkit for developing with HTML, CSS, and JS. Quickly prototype your ideas or build your entire app with our Sass variables and mixins, responsive grid system, extensive prebuilt components, and powerful plugins built on jQuery.

A design element gallery for web designers and web developers. Find snippets using HTML, CSS, Javascript, jQuery, and Bootstrap

Start Bootstrap develops free to download, open source Bootstrap 4 themes, templates, and snippets and creates guides and tutorials to help you learn more about designing and developing with Bootstrap.

A powerful web design tool for creating responsive websites using the Bootstrap framework.

Pingendo features a super simple drag and drop interface, with a rich library of prebuilt elements that lets you create web pages with ease. It produces just plain HTML, SASS and CSS to keep things simple, fully customizable and easily integrable with Javascript. Integrates a text editor for live coding and a set of premaid templates.

Core value: The ability for someone to add Bootstrap 4 to their resumé in 24 hours or less. Problem: Existing books/courses re-explain what is already found in the official docs, is often out of date, takes too much time, hard to distribute to a classroom or team, not written for beginners, and it's hard to get help if you have questions.