What is React?

React:

• React was designed around the idea that your UI should automatically react when your application's state changes.
• Instead of manually manipulating the DOM (like in plain JavaScript or jQuery), React lets you declare what the UI should look like, and it reacts to updates.

It’s called React because the UI reacts to data changes automatically.

React was created by Jordan Walke, a software engineer at Facebook (now Meta), around 2011–2013.

• It was first used internally at Facebook for their News Feed. 
• Later, it was open-sourced in May 2013 under the name React (or React.js)

React is a Javascript UI library for developing client based applications (browsers).