Browser Support

Gatsby supports the same browsers as the current stable version of React.js which is currently IE9+ as well as the most recent versions of other popular browsers.

Polyfills

Gatsby uses the ES6 Promise API. As some older browsers don’t support this, Gatsby includes by default a Promise polyfill. If you would like to provide your own Promise polyfill, you can set polyfill to false in your gatsby-config.js:

module.exports = {
  polyfill: false,
  // ...
}

Specify what browsers your project supports using “Browserslist”

You may customize your list of supported browser versions by declaring a "browserslist" key within your package.json. Changing these values will modify your JavaScript (via babel-preset-env) and your CSS (via autoprefixer) output.

This article is a good introduction to the growing community of tools around Browserslist — https://css-tricks.com/browserlist-good-idea/

By default, Gatsby emulates the following config:

// package.json
{
 "browserslist": [
   "> 1%",
   "IE >= 9",
   "last 2 versions"
 ]
}