browser-compat-data

This repository contains a large structured dataset recording which web features are supported by which browsers and JavaScript runtimes. It covers Web APIs (things browsers expose to JavaScript), CSS properties, HTML elements, and JavaScript language features. For each feature it records the browser version in which support was added, any versions in which it was removed, whether it is behind a flag or prefix, and similar details. The data is maintained by Mozilla and used as the source for the compatibility tables shown on the MDN Web Docs website.

The data is stored as JSON files organized by technology area, and the whole set is published as an npm package called @mdn/browser-compat-data. Developers can install it via npm or yarn and then import it into their own tools and applications to query browser support information programmatically. Import examples are provided for modern Node.js (ESM with import attributes), older Node.js versions, Deno, and browser environments via a CDN.

Beyond MDN Web Docs itself, this dataset is used by tools like CanIUse, Visual Studio Code, and WebStorm to show developers inline compatibility information while they write code. Because the dataset is machine-readable and versioned on npm, any project that cares about cross-browser compatibility can import it and build on top of it.

The repository is community-maintained and open to contributions. A governance document explains how decisions are made, and a contributing guide outlines the process for submitting changes. The project has a community chat channel on Matrix. The documentation index provides an alphabetical listing of all the documentation files covering data formats, schema definitions, and contribution guidelines.