This repository contains compatibility data for Web technologies as displayed on MDN
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api Add StorageManager API compat data (#2272) Jul 20, 2018
browsers browsers/nodejs.json: update Node.js versions (#2294) Jul 12, 2018
css Edge + Overflow-Wrap (#2406) Jul 19, 2018
html Mark spellcheck global attribute as not-experimental (#2488) Jul 18, 2018
http HTTP/Headers: add X-DNS-Prefetch-Control (#2256) Jul 19, 2018
javascript Add NodeJS versions for some features (#2196) Jul 19, 2018
mathml/elements Add <munder> (#2190) Jun 4, 2018
schemas Update JSON schema to require status block (#2382) Jul 16, 2018
svg Bug 1451823: Additions to SVG <a> element (#2018) May 15, 2018
test lint: print relative filepath (#2464) Jul 20, 2018
webdriver/commands Rename WebDriver JSON files. Apr 23, 2018
webextensions Add `images` and `properties` sub-keys to the `theme` manifest.json k… Jul 11, 2018
.editorconfig Add .editorconfig file and fix files (#188) May 16, 2017
.gitignore gitignore: ignore log files (#2216) Jul 13, 2018
.npmignore Refactor browser data (#834) Jan 28, 2018
.travis.yml Add npm as a deployment provider to travis Oct 30, 2017 Add code of conduct (#181) May 8, 2017 Add docs for publishing a new package version (#2480) Jul 16, 2018
LICENSE Add CC0 license (#175) May 6, 2017 Add “Visual Studio Code” to “Projects using the data” (#2432) Jul 9, 2018
index.js Use strict mode for the linter (#2288) Jun 20, 2018
package-lock.json 43rd alpha version Jul 19, 2018
package.json 43rd alpha version Jul 19, 2018


This repository contains compatibility data for Web technologies. Browser compatibility data describes which platforms (where "platforms" are usually, but not always, web browsers) support particular Web APIs.

This data can be used in documentation, to build compatibility tables listing browser support for APIs. For example: Browser support for WebExtension APIs.

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Maintained by the MDN team at Mozilla.


You can install mdn-browser-compat-data as a node package.

npm install mdn-browser-compat-data


const bcd = require('mdn-browser-compat-data');;
// returns a compat data object (see schema)

Repository contents

There's a top-level directory for each broad area covered: for example, "http", "javascript", "webextensions". Inside each of these directories is one or more JSON file containing the compatibility data.

Please note that we have not (yet) migrated all compatibility data from the MDN wiki pages into this repository.

  • api/ contains data for each Web API interface.

  • css/ contains data for CSS properties, selectors, and at-rules.

  • html/ contains data for HTML elements, attributes, and global attributes.

  • http/ contains data for HTTP headers, statuses, and methods.

  • javascript/ contains data for JavaScript built-in Objects, statement, operators, and other ECMAScript language features.

  • mathml/ contains data for MathML elements, attributes, and global attributes.

  • svg/ contains data for SVG elements, attributes, and global attributes.

  • webdriver/ contains data for WebDriver commands.

  • webextensions/ contains data for WebExtensions JavaScript APIs and manifest keys.

Format of the browser compat json files

The definitive description of the format used to represent compatibility data is the schema file. You can also have a look at the schema documentation.

Please note that we do not (yet) guarantee the stability of the data format. You're welcome to use the data, but its structure is subject to change without notice.


If you find a problem, please file a bug.


We're very happy to accept contributions to this data. Please familiarize yourself with the schema and send us a pull request. See also the Contributing file for more information.

Browser compatibility tables on MDN

It takes 1-2 weeks for changes in this data to be reflected in MDN's browser compatibility tables. The process is:

  1. A pull request is reviewed and merged to master.
  2. A new release of mdn-browser-compat-data is created by MDN staff. This happens every 4-14 days.
  3. A new image of Kumascript, which includes the BCD release, is built and deployed to production. This happens within a day of the npm package release.
  4. The MDN page using the data is regenerated. For newly converted pages, a staff member switches to the {{Compat}} macro, and re-checks the conversion. For updates to converted pages, a logged-in MDN user force-refreshes the page to regenerate it.

Projects using the data

Here are some projects using the data, as an npm module or directly: