EPUB 3 Accessibility Guidelines

Schema.org Accessibility Metadata

The schema.org CreativeWork class includes properties defined by the Acessibility Metadata Project that can be used to identify the accessible qualities of a publication. This metadata can be expressed in XHTML content documents using RDFa or microdata attributes to identify the accessible qualities of the content (e.g., videos). It can also be included in the EPUB package document to provide an overall picture of the accessibility of the given rendition of the publication.


Until EPUB 3.0.1 becomes a recommended specification, and epubcheck is updated, the schema: prefix in the examples on this page has to be declared in the package document using the epub:prefix attribute.

accessMode [draft]

This property is still under discussion and not yet formally a part of schema.org.

An access mode through which the intellectual content of a described resource or adaptation is communicated (i.e., the human sensory perceptual system or cognitive faculty through which a person may process or perceive information). If adaptations for the resource are known, the access modes of those adaptations are not included.

The following values are recommended for this property:

  • auditory
  • colorDependent
  • tactile
  • textual
  • visual
  • visual/chart
  • visual/chem
  • visual/diagram
  • visual/math
  • visual/music
  • visual/text

This property is related to the rendition:accessMode property proposed for rendition selection.

Package Document usage:

<meta property="schema:accessMode">textual</meta>

XHTML Content Documents usage: (RDFa)

<meta property="accessMode" content="textual"/>

Content features of the resource, such as accessible media, supported enhancements for accessibility and alternatives.

The following values are recommended for this property:

  • alternativeText
  • audioDescription
  • braille
  • captions
  • ChemML
  • displayTransformability
  • enhancedAudio
  • highContrast
  • largePrint
  • latex
  • longDescription
  • MathML
  • resizeText
  • signLanguage
  • structuralNavigation
  • tactileGraphic
  • tactileObject
  • transcript

Package Document usage:

<meta property="schema:accessibilityFeature">captions</meta>

XHTML Content Documents usage: (RDFa)

<p>Video includes <span 

A characteristic of the described resource that is physiologically dangerous to some users. Related to WCAG 2.0 guideline 2.3.

The following values are recommended for this property:

  • flashing
  • motionSimulation
  • sound

It is recommended that the above properties all be set either in the positive or negative sense. To indicate that no flashing hazard is known to exist, the value would be "noFlashing". The same pattern is used for the other two properties.

A publication that omits some or all of these properties is assumed to have not been checked for that hazard.

Package Document usage:

<meta property="schema:accessibilityHazard">flashing</meta>

XHTML Content Documents usage: (RDFa)

<p><strong>Warning</strong>: <span
in this video may cause seizures in some 

Identifies one or more input methods can be used that allow access to all of the application functionality.

The following values are recommended for this property:

  • fullAudioControl
  • fullKeyboardControl
  • fullMouseControl
  • fullTouchControl
  • fullVideoControl
  • timing

Package Document usage:

<meta property="schema:accessibilityControl">

XHTML Content Documents usage: (RDFa)

<meta property="accessibilityControl" content="fullKeyboardControl"/>

Indicates that the resource is compatible with the referenced accessibility API.

The following values are recommended for this property:

  • AndroidAccessibility
  • ARIA
  • ATK
  • AT-SPI
  • BlackberryAccessibility
  • iAccessible2
  • iOSAccessibility
  • JavaAccessibility
  • MacOSXAccessibility
  • MSAA
  • UIAutomation

Package Document usage:

<meta property="schema:accessibilityAPI">ARIA</meta>

XHTML Content Documents usage: (microdata)

<meta itemprop="accessibilityFeature" content="ARIA"/>


Example 1 — Package Document metadata

The following example shows a typical set of metadata for a math textbook with MathML and described images, and that includes accessible scripted content.

  <meta property="schema:accessibilityFeature">structuralNavigation</meta>
  <meta property="schema:accessibilityFeature">MathML</meta>
  <meta property="schema:accessibilityFeature">alternativeText</meta>
  <meta property="schema:accessibilityFeature">longDescriptions</meta>
  <meta property="schema:accessibilityAPI">ARIA</meta>
  <meta property="schema:accessibilityControl">fullKeyboardControl</meta>
  <meta property="schema:accessibilityControl">fullMouseControl</meta>
  <meta property="schema:accessibilityControl">fullTouchControl</meta>
  <meta property="schema:accessibilityHazard">noFlashing</meta>
  <meta property="schema:accessibilityHazard">noSound</meta>
  <meta property="schema:accessibilityHazard">noMotionSimulation</meta>
Example 2 — Embedded video metadata
<div vocab="http://www.schema.org" typeof="VideoObject" property="video">
  <video controls="controls" src="croc.mp4"/>
  <meta property="accessibilityFeature">captions</meta>
  <meta property="accessibilityFeature">transcript</meta>
  <meta property="accessibilityControl">fullKeyboardControl</meta>
  <meta property="accessibilityControl">fullMouseControl</meta>
  <meta property="accessibilityControl">fullTouchControl</meta>
  <meta property="accessibilityHazard">noFlashing</meta>
  <meta property="accessibilityHazard">noSound</meta>
  <meta property="accessibilityHazard">noMotionSimulation</meta>
  <p>A transcript of the video follows:</p>

Compliance References and Standards

Additional Resources