General Overview

This document will help those who wish to provide accessibility metadata directly to users understand how to represent machine readable accessibility metadata in a user friendly User Interface / User Experience (UI/UX).

Metadata found either inside an EPUB or in its corresponding ONIX file may have important accessibility information that will help end users find and determine if this EPUB can meet their specific accessibility needs.

Most metadata is meant to be machine readable so that it can be used to aid in user search queries such as Find all EPUB books that contain large print, or braille, or that has met a certain level of accessibility conformance. The exception to this is the accessibility summary which, if present, describes in human-readable text all the accessibility features and any shortcomings present in this book that can be directly presented to the end user.

All images provided here may be protected under copyright and are only used as a reference.

Here is an example of what a user-friendly accessibility metadata web page could look like:

Discovering Accessible Content

The guidelines for presentation of accessibility metadata in this document are intended to improve the user experience when readers browse the catalog entry for a book. However, accessibility metadata also has a vital role to play in helping readers discover books that are accessible for them. Book providers, vendors, and libraries are encouraged to create searching and filtering tools that interpret accessibility metadata to aid in discovery; a full discussion of this topic is out of scope for this document, but these brief notes may be helpful until further research and development leads to more specific guidance.

While every user has different accessibility needs, meeting the Web Content Accessibility Guidelines (WCAG) 2.0 requirements, even at level A, is a baseline that ensures a book will be widely accessible. Book providers may therefore wish to create specific search capabilities to permit users to find books that have declared conformance to WCAG at any level. A search filter called Accessible that retrieves all books with metadata of <link rel="dcterms:conformsTo" href="" /> or the equivalent for wcag-aa and ultimately for wcag-aaa would fill this need.

Audiobooks created for mainstream use provide important access for many users with disabilities even though they are not accessible to others. Book providers may already have search tools aimed at finding audiobooks, since they are popular and fairly common, but if not, this would be a good addition to the suite of tools for finding accessible books. Note that audiobooks may not pass WCAG requirements because they are targeted at a specific audience rather than broadly accessible and so would not be found using the Accessible search suggested above.

Any of the metadata fields discussed in detail below could also be used as a filter; a Screen-reader accessible search would be valued by screen reader users, and a way to ensure no books with hazards are downloaded would be valued by those with light-sensitive epilepsy or other hazard-related conditions. But if a single additional search filter fits best in a site’s UI, a tool for finding accessible materials that declare conformance to WCAG 2.0 is the most likely choice.

UI Technical Details

When you have accessibility metadata about an EPUB it is important to share this information with the user in a user friendly way. At a very high level when displaying information about an EPUB you may just want to acknowledge that there is Accessibility Features or Accessibility Information available and if the user would like to get at this information they can click a link or an image which will then provide the information that is discussed below.

For Example:



Order of Key Information

  1. Screen Reader Friendly

  2. Audiobook (if present)

  3. Accessibility Summary

  4. Accessibility Conformance

  5. Certified By

  6. Certifier’s Credential

  7. Certifier’s Report (if present)

  8. Hazards

  9. All Accessibility Metadata

Screen Reader Friendly

Value: Yes / No / Unknown


A Yes/No/Unknown answer to the question "Can a screen-reader user read this publication?". This can be based on a combination of metadata fields, if needed, that establish that the primary content of the publication is available in true text and is not an image of text.


Most available digital publications include their content in true text and can report that they are screen reader friendly. Exceptions would include publications where critical content is included only in images, such as graphs, charts, or equations presented as images, and publications with a fixed appearance created by having an image of each page instead of true text.


Values: Yes / (if No - Omit this section)


An indication that this publication is an audiobook which is designed to be used by listening. This designation can be applied if text will also appear on a display as long as it is not required to use the publication.


Audiobooks are considered optimized publications. They may not meet all accessibility requirements if they lack visible text, but they provide access to the publication for specific users who require audio, including users with dyslexia or visual impairments. Providing a way for users to search a collection for audiobooks will support these users, and including this information in the metadata displayed will also alert users for whom audio is inaccessible. This piece of metadata should be included only if the value is "Yes". Since most digital publications available are not audiobooks, it is only important to include this metadata in the user interface for those that are.

Accessibility Summary

Value: Textual Data from metadata


A plain language explanation of the overall accessibility of the publication. The accessibility summary should contain information that would make it easy for an end user to determine if the publication is accessible to them. Educators would also be able to determine if the publication was accessible for use in a classroom or an online course.


A human readable description is needed to be available for an end user or an educational professional to determine if the title will be accessible to them personally, or to the students. It should be easy to read and understand if it will be suitable for use by persons with disabilities. This determination must be made before the end user purchases or selects the title, and must be determined before a title is selected for a course.

Accessibility Conformance

Value: Textual Link based on Metadata (WCAG-A, WCAG-AA, WCAG-AAA)


To report the accessibility conformance of a publication, the metadata term conformsTo must be provided. The conformsTo term requires a specific URL that identifies the level of conformance of the publication. The values for an EPUB publication are:

The above URLs indicate that the publication meets the EPUB accessibility requirements and the corresponding WCAG levels of A, AA, and AAA.

If a publication is optimized for a particular user group, e.g. an audiobook, it would not conform to WCAG guidelines, but it may be perfectly useable by a particular group, e.g. persons who are blind. In this case, the conformsTo term must point to a URL that identifies the specification used to create the optimized publication.


Discovery metadata enables publications to have their accessibility exposed regardless of the overall accessibility of the publication. A publication optimized for a particular group, such as an audiobook, would not meet WCAG 2.0, but it would be fully accessible to many people. The conformance metadata details the accessibility of the publication, which allows end users and educators to evaluate the suitability of the publication for individuals.

Certified By

Value: Textual Data from metadata


The Certified By property specifies the name of the party that certified the content. The certifier of the content could be the same party that created or published the publication, but can also be a third-party accessibility certifier.


When the metadata about a publication declares that it conforms to an accessibility specification reaching a certain level of WCAG conformance, the party making this assertion must be identified.

Certifier Credential

Value: Potentially linked textual data from metadata


The Certifier Credential indicates the name of the credential or badge that establishes the authority of the certifying party.


Stating that the organization certifying this content has a credential recognized by the community gives a higher level of trust as to the accuracy of the conformance level reached.

Certifier Report

Value: Potentially linked textual data from metadata


The Certifier Report is an URL pointing to a web page where the certifier publishes a report detailing the accessibility of the publication.


Providing a link to the complete report allows end users and organizations to review it. The user interface should display a link to the report.


Values: flashing, motion simulation, sound, no flashing, no motion simulation, no sound, none, or unknown.


Hazards are a list of possible ways in which this publication could be physiologically dangerous for some users (e.g. flashing elements, background sounds, motion simulation, etc.).


Unlike other accessibility properties, the presence of hazards can be expressed either positively or negatively. This is because users are more often looking for content that is safe for them. This section should always be displayed; indicate that no metadata was provided if that is the case.

All Accessibility Metadata

Value: Link to complete list of all metadata fields


It is a pointer to show the listing of all the accessibility metadata of the publication. It can be a hyperlink to another page or can be listed in HTML summary/details element. It should include metadata for accessibilityFeature, accessibilityHazard, accessMode, accessModeSufficient and all the accessibility metadata and conformance metadata listed above.


A complete list of accessibility metadata is important for advanced users who would like to know about the presence of specific accessibility features in the publication. This listing is also important for verification of the interpretation of the accessibility metadata provided according to this user experience guide.