Babel (transcompiler)

Babel
Original author	Sebastian McKenzie
Developer	Contributors
Initial release	September 28, 2014 (2014-09-28)1
Stable release	7.29.72  / 25 May 2026 (25 May 2026)
Written in	JavaScript
Operating system	Linux, macOS, Solaris, FreeBSD, OpenBSD, AIX, Microsoft Windows
Type	Compiler
License	MIT3
Website	babeljs.io
Repository	github.com/babel/babel

Babel is a free and open-source JavaScript transcompiler that is mainly used to convert ECMAScript 2015+ (ES6+) code into backwards-compatible JavaScript code that can be run by older JavaScript engines. It allows web developers to take advantage of the newest features of the language.⁴

Developers can use new JavaScript language features by using Babel to convert their source code into versions of JavaScript that a Web browser can process.⁵ Babel can also be used to compile TypeScript into JavaScript.⁶ The core version of Babel was downloaded 5 million times a month in 2016, and this increased to 16 million times a week in 2019.⁷⁸

Babel plugins transform syntax that is not widely supported into a backward-compatible version. For example, arrow functions, which are specified in ES6, are converted into regular function declarations.⁹ Non-standard JavaScript syntax such as JSX can also be transformed.¹⁰¹¹

Babel can automatically inject polyfills provided by core-js¹² for support features that are missing entirely from JavaScript environments. For example, static methods such as Array.from and built-ins such as Promise are available only in ES6 and above, but they can be used in older environments if core-js is used.