What is the different between using React Js and Next Js?

I use NextJs whenever I’ve to develop something for React.
The benefits I get from NextJs over Create React App are :-

1. Server side rendering.
2. Out of the box routing.
3. Ability to write server-less functions.

Hope this helps.

Next.js is just a higher abstraction of React. Think it this way.

Language (JavaScript) -> Library (React) -> Framework (Next)

The higher the abstraction the more opinionated it is.

Why Next.js?

• Performant out of the box.
• One framework can be used for multiple prerendering methods like server-side rendering (SSR), and static site generation (SSG) on a per-page basis.

React is s library for building user interfaces.

Next.js uses React. It's a framework for server-rendered React applications.