JSX stands for JavaScript XML. JSX is a preprocessor step that adds XML syntax to JavaScript. This is a type of file used by React which utilizes the expressiveness of JavaScript along with HTML like template syntax and this makes the HTML file really easy to understand. Tuning the React code into JSX increases the application performance from the client-side.

Example:-

render(){
  return(
    <div>
    <h1> Slightbook!!!</h1>
    </div>
 ?);
}