Browserslist Generator

It is a shared way to declare which browsers a project supports. Babel, Autoprefixer, PostCSS, esbuild, Vite, and many other tools read the same query list to decide which transforms, prefixes, and polyfills to emit.

Defaults inserts Browserslist's own 'defaults' query. Modern seeds 'last 2 versions' and 'not dead' for recent, maintained browsers. Wide starts from '> 0.2%', 'not dead', and 'not ie 11' to reach a broad, still-current audience.

It selects browser versions used by at least that share of global traffic, based on Can I Use statistics. A smaller percentage widens support to older or rarer browsers; a larger one narrows it.

Queries are assembled in a fixed order: preset lines first, then last N versions, then the coverage query, then not dead, then not ie 11, then your custom lines. Exact duplicates are dropped, keeping the first occurrence.

A coverage percent must be between 0 and 100 and a version count must be a whole number of at least 1. An out-of-range value produces a comment line describing the error instead of a config, so nothing broken is copied.

Yes. Type them in the custom box, one per line, and they are appended verbatim after trimming. This is how you add things like 'Firefox ESR', 'maintained node versions', or 'iOS >= 15'.

Save it as .browserslistrc in your project root, next to package.json. Alternatively you can move the same lines into a 'browserslist' key in package.json; the tool gives you the standalone file form.

No. It builds the query text and checks the numeric ranges, but it does not run Browserslist against the caniuse database, so it will not tell you how many browsers a query actually matches today.

Yes. The file is generated entirely in your browser and nothing is uploaded, so your target list stays on your machine.