EPUB to ONIX Accessibility Metadata Guide

Follow this step-by-step guide to extract accessibility metadata from your EPUB and translate it into ONIX.

  • Subject(s):


  • Resource Type(s):


  • Audience:


Suggested Prerequisite

Before reading this, you might want to read:


This resource was authored by Amanda Lee, Metadata Consultant. Amanda has worked in Canadian publishing for over 10 years. As an independent consultant, Amanda has managed projects focused on using accessible publishing or metadata to ensure everyone looking for a Canadian book can get it. Those projects include managing metadata workflows for Canadian publishers, training publishers in enhanced metadata and digital distribution, researching the state of accessible book publishing, researching the effects of specific pieces of metadata on sales of books, and more.


Step One: Run Your EPUB Through Ace

Drag your EPUB file into the Ace by DAISY main screen or use the “Check EPUB” button. Once it’s processed, click into the Metadata tab (highlighted below).

A screenshot of the application Ace by DAISY, open to the metadata tab. A yellow box highlights the word Metadata at the top and the Accessibility filter on the top right corner. Several schema accessibility metadata properties are listed on the tab.

Sort the metadata by Accessibility (highlighted).

Step Two: Translate to ONIX Using the Crosswalk

Open the Accessibility Properties Crosswalk. Using the metadata in Ace, match each item in the Name column to a header in the crosswalk. Then, find the item in the Value column in the related column of the crosswalk and copy down the instructions to convert to ONIX. Repeat until you’ve got every metadata feature represented (or as many as possible).

For example, to find this item…

Cropped screenshot of the Ace by DAISY app. The item schema:accessMode and values textual and visual are listed in the Metadata tab.

  1. Find the header for accessMode in the crosswalk
  2. Look through the accessMode table for “textual” in the Schema.org column
  3. Copy down the information in the ONIX column: “List: 81; Code: 10 combined with List: 196; Code: 10 means all text is actual text.”
Cropped screenshot from the accessibility properties crosswalk. The text reads 3.5 accessMode, The human sensory perceptual system or cognitive faculty through which a person may process or perceive information.

Step Three: Translate to Human-Readable ONIX using the ONIX Codelists

Open the ONIX Codelists (available with easy navigation at onix-codelists.io or using the official EDItEUR codelist browser).

Find the lists indicated in the information you entered. Find the codes within the list and copy them down. Repeat until you’ve got every metadata feature represented (or as many as possible).

Using the example above, which was “List: 81; Code: 10 combined with List: 196; Code: 10 means all text is actual text.”, you would…

  1. Find list 81 and write down the list name: “product content type”
  2. Find code 10 on list 81 and write down the code: “10 Text”
  3. Find list 196 and write down the name: “E-publication Accessibility Details”
  4. Find code 10 on list 196 and write down the code: “10  No reading system accessibility options actively disabled (except)”

Step Four: Enter the Information into Your Database

ONIX is the metadata that is produced by your database (such as CoreSource, BooksoniX, ONIXEdit, BookConnect, etc.) or your distributor’s database. When you enter information—not just accessibility data but any metadata—into your database it lives there. When that data is “distributed”, “disseminated”, or any other term that means “sent”, it gets converted to an ONIX file. That ONIX file, which looks a lot like HTML code, is loaded by your trading partners into their own databases, which then power the way data is displayed on their websites. 

ONIX is a very robust set of codes that can be somewhat limited by the capabilities of your databases. In your database, you’re looking for Accessibility Metadata or E-publication Accessibility Details, where you would enter the applicable accessibility metadata information.

Below is an example from the CoreSource platform. In your EPUB asset’s Basic Information tab, search for the “Product Form Feature(s)” field and add the applicable metadata. Currently, this can be done manually for each title via the user interface, or for multiple titles through CoreSource’s metadata spreadsheet.

Screenshot of the Product Form Features field in CoreSource. Under the Type heading the code 09 - E-publication accessibility detail is selected.

Next Steps


Understanding and Creating Schema.org Metadata for Ebooks

Introduction to Schema.org Accessibility Metadata

This resource defines all of the schema.org accessibility metadata properties and provides guidance on what to include in your OPF file.

Subject(s): Metadata
Resource Type(s): Standards and Best Practices

Creating Accessibility Metadata for an ONIX Record

Introduction to ONIX Metadata for Ebooks (and the Supply Chain)

This resource discusses the importance of ONIX accessibility metadata, and shares an example of the accessibility section of an ONIX file.

Subject(s): Metadata
Resource Type(s): Foundations and Rationale, Standards and Best Practices

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