This vocabulary defines properties for describing the accessibility of EPUB Publications in the Package Document metadata.

This document is subject to change at any time. The terms defined herein will never be removed, but may be deprecated.

Any use of terms marked [draft] should be considered experimental.

Deprecated term are identified by the label [deprecated]. These terms are no longer recommended for use.


About this Vocabulary

This vocabulary is a companion to the EPUB Accessibility specification and is intended to be read in conjunction with that document.


The base IRI for referencing this vocabulary is

The prefix "a11y:" is reserved for use with properties in this vocabulary and does not have to be declared in the Package Document.


Terms with meanings specific to EPUB are capitalized in this document (e.g., "Author", "Reading System"). See the EPUB Accessibility specification for their meanings.

Only the first instance of a term in a section is linked to its definition.

Conformance Properties


Name: certifiedBy
Description: Identifies a party responsible for the testing and certification of the accessibility of an EPUB Publication.
Allowed value(s): xsd:string
Cardinality: One or more
Example: <meta property="a11y:certifiedBy">Accessibility Testers Group</meta>


Name: certifierCredential
Description: Identifies a credential or badge that establishes the authority of the party identified in the certifiedBy property to certify content accessible.
Allowed value(s): xsd:string
Cardinality: Zero or more
Example: <meta property="a11y:certifierCredential">DAISY OK</meta>


Name: certifierReport
Description: Provides a link to an accessibility report created by the party identified in the certifiedBy property.
Allowed value(s): xsd:anyURI
Cardinality: Zero or more
Example: <link rel="a11y:certifierReport" href=""/>