Bootstrap is a free and open-source front-end framework for designing websites and web applications. It contains HTML and CSS-based design templates for typography, forms, buttons, navigation and other interface components, as well as optional JavaScript extensions.
Heap is a web and mobile analytics solution which automatically records all actions taken in web & iOS apps, and allows users to define new events without code.
Wix is a website building & publishing platform which helps users create professional websites exactly the way they want, with a drag & drop website editor.