Bringing accessibility support data to developer tools

Browser compatibility data doesn't tell you if a feature works with assistive technology. Accessibility Compatibility Dataset (ACD) The dataset which includes the accessibility interoperability support data for browser and assistive technology combinations. adds accessibility support data to the tools developers already use, working with Mozilla, Browser Compatibility Data (BCD) The browser-compat-data project contains machine-readable browser (and JavaScript runtime) compatibility data for Web technologies, such as Web APIs, JavaScript features, CSS properties and more. BCD is used in web apps and software such as MDN Web Docs, CanIUse, Visual Studio Code, WebStorm and more., ARIA-AT The assistive technology test suite which includes tests for patterns defined in the ARIA Authoring Practices Guide and some HTML web-features. and Baseline Identifies the availability of web platform features across popular browsers, including APIs, CSS properties, and JavaScript syntax. This project is owned by multiple stakeholders including Microsoft and Google.. Support data doesn't tell you whether a feature is accessible, it shows where browsers and screen readers fall short, so you can plan workarounds.

Illustrative example for <button> not real data
Chrome 140 Edge 140 Firefox 143 Safari 26
JAWS 2025 Supported Supported Partial Browser fails Not applicable
NVDA 2025.3 Partial Screen reader fails Partial Screen reader fails Unsupported Browser and screen reader fail Not applicable
VoiceOver macOS 26 Not tested Not tested Not tested Partial Browser fails

"Supported" doesn't mean "accessible". ACD shows you where support gaps are, so you can add fallbacks before users hit them.

View as machine-readable data 
{
  "feature": "html.elements.button",
  "results": [
    { "screen_reader": { "name": "jaws", "version": "2025" },
      "browser": { "name": "chrome", "version": "140" },
      "status": "supported", "notes": [] },
    { "screen_reader": { "name": "jaws", "version": "2025" },
      "browser": { "name": "edge", "version": "140" },
      "status": "supported", "notes": [] },
    { "screen_reader": { "name": "jaws", "version": "2025" },
      "browser": { "name": "firefox", "version": "143" },
      "status": "partial", "notes": ["Browser fails"] },
    { "screen_reader": { "name": "jaws", "version": "2025" },
      "browser": { "name": "safari", "version": "26" },
      "status": "not_applicable", "notes": [] },
    { "screen_reader": { "name": "nvda", "version": "2025.3" },
      "browser": { "name": "chrome", "version": "140" },
      "status": "partial", "notes": ["Screen reader fails"] },
    { "screen_reader": { "name": "nvda", "version": "2025.3" },
      "browser": { "name": "edge", "version": "140" },
      "status": "partial", "notes": ["Screen reader fails"] },
    { "screen_reader": { "name": "nvda", "version": "2025.3" },
      "browser": { "name": "firefox", "version": "143" },
      "status": "unsupported", "notes": ["Browser and screen reader fail"] },
    { "screen_reader": { "name": "nvda", "version": "2025.3" },
      "browser": { "name": "safari", "version": "26" },
      "status": "not_applicable", "notes": [] },
    { "screen_reader": { "name": "voiceover", "version": "macOS 26" },
      "browser": { "name": "chrome", "version": "140" },
      "status": "not_tested", "notes": [] },
    { "screen_reader": { "name": "voiceover", "version": "macOS 26" },
      "browser": { "name": "edge", "version": "140" },
      "status": "not_tested", "notes": [] },
    { "screen_reader": { "name": "voiceover", "version": "macOS 26" },
      "browser": { "name": "firefox", "version": "143" },
      "status": "not_tested", "notes": [] },
    { "screen_reader": { "name": "voiceover", "version": "macOS 26" },
      "browser": { "name": "safari", "version": "26" },
      "status": "partial", "notes": ["Browser fails"] }
  ]
}

Roadmap

ACD is in early development but here's how we're going to get from tests to developer tools:

  1. Expand test coverage Add browser and screen-reader tests for HTML features to Web Platform Tests (WPT) The browser test suite which includes tests for every web feature. and ARIA-AT.
  2. Compute a support status Combine those results into a machine-readable support status for each feature.
  3. Bring it to developer tools Get the data into the tools developers already use, like MDN and Baseline.

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