Browser support¶

We serve JavaScript to any browser that supports fetch. We use esbuild to transpile and minify our JavaScript.
We prefix CSS for every browser in our browserslist. We use autoprefixer to add vendor-specific prefixes to rules where necessary.

Outputting browser support metrics¶

Within the root directory, run npx browserslist to output the set of browser targets given to autoprefixer (CSS) transpiling.

Note

A browserslist string is used in package.json. See the browserslist docs for information on this string and the defaults.

For JavaScript, esbuild uses the es6 target and our code conditionally includes JavaScript in browsers that support fetch.

Note

JavaScript may still be delivered to legacy browsers in the form of our analytics and related scripts.

Twice per year we aim to updated the browser metrics that are fed into our browserslist config at @cfpb/browserslist-config.

Per the best practices published by browserslist, we use a 0.2% cutoff with this config for the browsers that get fed into our build systems.

However, for what we actively aim to support and test, we use a higher cutoff of 1%. The current 1% cutoff list is:

and_chr 149
chrome 147
chrome 146
chrome 145
chrome 144
chrome 143
chrome 142
chrome 69
edge 144
edge 143
ios_saf 18.5-18.7