Accessibility Compat Data

What Is ACD?
Accessibility Compatibility Data (ACD) is a project to document
how web platform features are supported by assistive technologies (AT)
across different browsers. Inspired by the Browser Compatibility Data (BCD) project
which is integrated into developer resources like Mozilla Developer Network (MDN) and CanIUse,
ACD aims to bring accessibility interoperability data into the same developer ecosystem.

Why It Matters
Currently, developers have no integrated way to check if a feature that 'works in a browser'
is also accessible to people using screen readers or other AT.
Tools like MDN show browser support, but not how screen readers interpret those features.
Web features can be visible and functional in a browser but unusable with assistive tech.
ACD addresses this by:

Tracking how features behave across browser + AT combinations
Surfacing this data in places developers already use
Helping teams spot issues earlier and avoid costly accessibility fixes later

How is 'Accessible' Defined?
We will be using the WCAG 2.1 definition of accessibility-supported.

The way that the web content technology is used must be supported
by users' assistive technology (AT). This means that the way that
the technology is used has been tested for interoperability with
users' assistive technology in the human language(s) of the content,
AND
The web content technology must have accessibility-supported
user agents that are available to users. [...] The technology
is supported natively in widely-distributed user agents
that are also accessibility supported (such as HTML and CSS);

This means that the browser has to expose the web feature
to the accessibility tree **and** be supported by the AT.

Key Goals

Define a machine-readable dataset to represent accessibility support for web features
Integrate accessibility data into MDN and other developer tooling
Support developers in building accessible experiences from the start
Reduce compliance burdens by making accessibility interoperability data more visible
Improve web experiences for users of assistive technologies

What ACD Is Not
ACD is not an auditing tool and doesn’t evaluate entire websites. ACD does not define
a baseline, or mark features as generally accessible or inaccessible.
ACD should be used to identify potential accessibility gaps and opportunities
for developers to implement accessibility fallbacks for web features where necessary.

Current Focus (Research Phase)

Collaborating with browser vendors, documentation maintainers, and accessibility experts
Scoping the dataset shape and testing methodology
Running workshops and surveys to understand the needs of developers, accessibility professionals, and developer tooling maintainers.
Identifying integration paths into existing resources like MDN

Our team

Lola Odelola

Admin

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Jeffrey Yasskin

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mehm8128

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