JSX is a JavaScript extension that allows developers to describe Reacts object tree using a syntax that resembles that of an HTML template. Because JSX is not valid JavaScript, browsers can’t read it directly, so a transpiler is needed to translate it to React.createElement() calls. Transpilers are compilers that translate one form of syntax into another, like Babel or TypeScript, and they compile JSX into a browser-compatible version during the build process. The resulting code is a tree of objects that have been described using the React API.