Browser Support

Protocol supports:

• Firefox ESR and current Firefox
• Safari 15.6 and later (macOS and iOS)
• Chrome, Edge, and other “evergreen” browsers

This matrix is declared as the browserslist key in package.json, which drives both the Sass build’s CSS minification and the Babel target for the compiled JavaScript.

What this means for your project

If you compile Protocol’s Sass yourself, your own build tooling should target the same matrix (or a subset of it) to avoid re-introducing legacy CSS output.

Protocol no longer ships vendor-prefixed fallbacks, @supports feature-query fallbacks for older engines, or IE-era polyfills. If your project needs to support browsers outside this matrix, you’ll need to add your own fallback styles and polyfills.

Testing

Protocol’s automated test suite (npm test) runs unit tests in Firefox and Chrome. Safari is not currently covered by CI; if you rely on Safari support, we recommend a manual smoke test of your integration.