Just the UI
Lots of people use React as the V in MVC.
Since React makes no assumptions about the rest of your technology stack, it's easy to try it out on a small feature in an existing project.
React uses a virtual DOM diff implementation for ultra-high performance.
It can also render on the server using Node.js — no heavy browser DOM required.
React implements one-way reactive data flow which reduces boilerplate and is easier to reason about than traditional data binding.
Instagram.com is 100% built on React, both public site and internal tools.
Facebook.com's commenting interface, business management tools, Lookback video editor, page insights, and most, if not all, new JS development.
Khan Academy uses React for most new JS development.
Sberbank, Russia's number one bank, is built with React.
The New York Times's 2014 Red Carpet Project is built with React.
Image / Source:http://facebook.github.io/react
GitHub / Download:https://github.com/facebook/react
Apache License, Version 2.0http://www.apache.org/licenses/LICENSE-2.0https://github.com/facebook/react/blob/master/LICENSE