JavaScript XML is what JSX stands for. We can write HTML in JavaScript and put it in the DOM without having to use tools like createElement() or appendChild(). 

It is written in the official React documentation that JSX gives React extra syntax.method that creates an element. 

It's also possible to make React apps without using JSX.

 

Without using JSX

const container = (
   <div> <p>This is a text</p></div>
);
ReactDOM.render(container,rootElement);

Can doing similar using JSX

const text = React.createElement('p', {}, 'This is a text');
const container = React.createElement('div','{}',text );
ReactDOM.render(container,rootElement);