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.

Current browser support metrics¶

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 123
chrome 126
chrome 125
chrome 124
chrome 123
chrome 122
chrome 121
chrome 120
edge 124
edge 123
edge 122
edge 121
edge 120
ios_saf 17.5
ios_saf 17.4
ios_saf 17.3
ios_saf 17.2
ios_saf 17.1
ios_saf 16.6-16.7