The MDN Browser Compatibility Data Repository

What is the BCD?

The Browser Compatibility Data (BCD) repository is a structured, regularly updated record of support for HTML, CSS, and Javascript features in multiple desktop and mobile browsers.

Where applicable, it includes detailed information about the level of support provided, along with links to associated bug reports. Deprecated features are indicated, as well as those which require prefixes and flags to activate.

This data is maintained by the MDN community, in cooperation with browser vendors and industry experts from the Product Advisory Board. It is available on GitHub in JSON files and as an npm package.

Why would you use the BCD?

The reality of the web is that vendors independently modify their support for features, older browsers are still widely used, and mobile devices add another layer of complexity.

In this landscape, portable compatibility data significantly increases the usefulness of web development tools. It can also be used to analyze historical feature trends or specific code bases. For example, you could use the data to measure CSS properties growth in Firefox versions.

How can you use the BCD?

The easiest way is to try out one of the variety of tools that are already integrated with the BCD.

Your next best option is to explore the npm package.

Visit the repository

Explore the npm package

The BCD on MDN

Compatibility tables are included in MDN articles about HTML, CSS, and Javascript features.

A HTML BCD table: Input

A CSS BCD table: prefers-color-scheme

A Javascript BCD table: Intl.PluralRules

Tools and Resources Integrated With the BCD


Firefox Developer Tools

The Compatibility panel in the Developer Tools Inspector of Firefox Nightly and Developer Edition indicates which browsers and browser versions (e.g. mobile) are compatible with your CSS.

Get Firefox Developer Edition


Provides regularly updated reference tables for front-end developers.

Try out caniuse


A linting tool used to improve websites' compatibility, speed, and accessibility.

Try out webhint

Visual Studio Code (also known as VS code)

A popular source code editor, also includes access to MDN reference material for HTML and CSS.

Details: Browser Compat Data

Details: Reference Access


A Javascript IDE that uses the BCD.

Learn More