This repository contains compatibility data for Web technologies as displayed on MDN
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Type Name Latest commit message Commit time
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.github Add initial pull request template (#3208) Dec 13, 2018
.vscode Add a VS Code snippet config for creating new BCD files. (#2939) Oct 29, 2018
api Updated browser support for document.adoptNode() (#3299) Jan 18, 2019
browsers Update Chrome browser releases (#3288) Jan 14, 2019
css fix(css): Correct the `::-webkit-scrollbar-track` selector data (#3306) Jan 18, 2019
html adding referrerPolicy for script elements compat data (#3301) Jan 17, 2019
http Fix issue #1702: Mark TRACE support as null (#3297) Jan 17, 2019
javascript Update Array.prototype.flat() support in Node.js (#3304) Jan 17, 2019
mathml/elements Add webview_android browser data (#2690) Sep 14, 2018
schemas schema: Require that a single note isn’t inside an array (#3090) Jan 9, 2019
scripts Move utility scripts to `scripts` directory (#3284) Jan 11, 2019
svg schema: Require that a single note isn’t inside an array (#3090) Jan 9, 2019
test Move utility scripts to `scripts` directory (#3284) Jan 11, 2019
webdriver/commands webdriver: fix typo and link to capabilities on mdn (#2930) Oct 10, 2018
webextensions BCD for closeTabsByDoubleClick (#3237) Jan 10, 2019
xpath/axes Setup XPath compat data (#2287) Aug 27, 2018
xslt/elements Add chrome_android release data and correct invalid versions (#1356) Aug 29, 2018
.editorconfig Add .editorconfig file and fix files (#188) May 16, 2017
.gitattributes Avoid line ending inconsistencies (#3231) Jan 7, 2019
.gitignore gitignore: ignore log files (#2216) Jul 13, 2018
.npmignore Add VisualStudio Code extension recommendations and basic settings (#… Aug 9, 2018
.travis.yml Add npm as a deployment provider to travis Oct 30, 2017 Add code of conduct (#181) May 8, 2017 Add a script to generate GitHub release notes (#3199) Jan 11, 2019
LICENSE Add CC0 license (#175) May 6, 2017 Update project listing in readme (#3265) Jan 8, 2019 Add note about false positives in Chrome 43 (#3279) Jan 11, 2019
index.d.ts Create TypeScript Definition File (#2308) Aug 20, 2018
index.js Make the linter print better error messages (#2338) Jan 7, 2019
package-lock.json 63rd alpha version Jan 17, 2019
package.json 63rd alpha version Jan 17, 2019


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.

  • xpath/ contains data for XPath axes, and functions.

  • xslt/ contains data for XSLT elements, attributes, and global attributes.

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: