Accessibility API Mapping

Accessibility API Mappings (AAMs) are W3C specifications that define how the semantics of web content technologies — such as HTML, SVG, and WAI-ARIA — correspond to features in platform accessibility APIs like MSAA/UIA on Windows, ATK/AT-SPI on Linux, and NSAccessibility on macOS. These mappings ensure that when a browser encounters an element like a checkbox or heading, it exposes consistent, interoperable information to assistive technologies regardless of the platform. Before formal AAM specifications existed, each browser implementer made their own interpretations of how to expose HTML semantics, leading to inconsistencies that affected screen reader behavior across browsers. Key AAM specifications include HTML-AAM, SVG-AAM, Core-AAM, and ARIA-AAM.