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ONIX (ONline Information eXchange) is a universal, international format enabling all publishers to exchange information about books.

The ONIX specification is developed and maintained by EDItEUR with direction from an International Steering Committee that includes representatives from many of the countries that have adopted ONIX (including Canada).

What is ONIX?

ONIX is a standard format or "language" that publishers need to use when distributing electronic information about books to wholesale, e-tail and retail booksellers, other publishers, and any other supply chain partner involved in the production, review or sale of books.

ONIX is not a database and you don't have to change your database in order to use it. Don't be worried by the acronym: it isn't a programming language and it can't "do" anything. It just describes. It's a file format for the delivery of book information.

You could also send this information via Excel spreadsheet, Delimited ASCII (tab or comma, with our without headings), Fixed width, HTML, Word, QuarkXpress, email message or hard copy, but ONIX is the preferred method.

ONIX Makes It Easier To Sell Books

Take a browse through any of the major online bookstores and you'll notice that some books have cover art, descriptions, review and other information (known as metadata), and others list nothing but the title, author and price. Metadata plays a large role in online book sales (titles with metadata outsell those without, eight to one) so it is in the best interest of both bookstores and publishers to include metadata for as many titles as possible.

Online retail's emergence as a popular new channel for buying books, albeit one that lacks the opportunity to physically pick up and browse a jacket cover, has been a key driver in the creation of ONIX. Books are promoted through written text on a web page. Getting this data about each book from publishers to booksellers proved complicated, especially as major industry retail databases used different format preferences for receiving bibliographic data. A standard format was, therefore, agreed upon as the optimum way for publishers to format and exchange their book information.

The major booksellers and distributors have moved towards this standardized format for bibliographic data, so that wholesalers, retailers and other suppliers can accept information that is transferred electronically in the ONIX format. The fact that publishers can create one file to push to all aspects of the supply chain means their bibliographic data is going to be represented.

The ONIX Message

The ONIX standard defines both a list of data fields about a publication and how to send that data in an ONIX message. ONIX specifies and defines the data elements so that everyone can be sure they're referring to the same thing. Publishers can use as many or as few of the data elements they wish to record and transmit. These are not just limited to facts and figures and textual description: multimedia files, such as images and audio files are becoming increasingly important as ways of encouraging sales and enriching the record.

The ONIX message is a set of data elements defined by tags written in XML (eXtensible Markup Language). This conforms with a DTD (Document Type Definition) which defines, among other things, how to order the data elements and how the elements are interrelated.

How Does ONIX Actually Work?

ONIX is a common language of terms and definitions, which describe the data fields needed to express the rich information publishers and retailers require. The standard is released once every few years so supporting code lists are constantly evolving.

It is also a standardized means of electronic delivery that uses recognizable XML tags for each data element. You can choose to use long tags (which are descriptive) or short tags (which aren't). ONIX uses a series of 148 data elements to describe book information. The data elements are simple identifiers enclosed in angle brackets. For example, the tag is used to indicate an ISBN, while identifies the title.

Of the 148 elements, 42 are designated as the kernel - the bare minimum that every publisher should supply about every book, though not all the kernel elements will apply to every book, and many of the non-kernel elements are very desirable to include as well. While it might sound complex, in reality ONIX is a simple format for even small publishers with limited budgets. ONIX-formatted files can be created with something as simple as a basic text editor or Microsoft's free XML Notepad or Simple Text.

The ONIX Document Type Definition (DTD) contains in its entirety over 230 data elements and composite elements, organized into 38 groups. Of these groups, 25 relate to product records, 6 to main series records and 7 to sub-series records.

Creating and Transferring ONIX Files

First, organize your book data into ONIX-specified fields and store it in a database. This can be done by using the BNC Bronze Template. Then, use the BNC ONIX Converter to organize and tag that data, thus creating an ONIX file.

The simplest way to transfer your data is via the Internet by way of an email attachment or FTP (file transfer protocol). First time submissions which contain an imprint or publisher name and new code may also need to be accompanied by an Excel or text file that lists the imprint or publisher's name and corresponding code. This will ensure that the codes are associated with the correct buying channels for purchasing. The retailer or distributor verifies the data and then translates it into the information you see on a web page.

The ONIX standard is now defined by ONIX 3.0 but ONIX 2.1 remains in use

ONIX 2.1 is no longer a supported standard.

As of early 2017 the ONIX 2.1 will not be further updated in any way past Code List Issue 36 (released January 2017).  It is the final code list for this version.  But being unsupported does not mean it is not used.  ONIX 2.1 may remain in use for however long two companies choose to continue to trade data using that version.  
In North America ONIX 2.1 continues to be used for almost all physical book metadata transfers and retailers are having difficulty finding enough ONIX 3.0 suppliers to begin to program to accept it.
BookNet Canada continues to recommends:
  • All data suppliers continue to support ONIX 2.1 for North American data transfer
  • If you can support ONIX 3.0 in addition to ONIX 2.1 please do so and ensure trading partners are aware of the option. This will facilitate retailers and other aggregators developing ONIX 3.0 support
  • No one should switch from ONIX 2.1 to ONIX 3.0 without first notifying their trading partners.  We think you'll find that you will still need to support ONIX 2.1
  • New implementations of ONIX have a hard decision:  ONIX 2.1 will not be supported for much longer but it remains the practical choice in our market.

ONIX 3.0 users should update their code lists for Issue 37 and beyond.  ONIX 2.1 users should use code list Issue 36 going forward.

If you need help, contact

ONIX 3.0 Revision 3

ONIX 3.0 is the new version on ONIX with better support for Digital Products and capable of a much higher degree of accuracy to support truly international data exchange. There have been a couple of major structural changes since it's inital release in 2009 and any implementer should ensure that they are using ONIX 3.0.3.

In North America actual use of ONIX 3.0 is still limited and most data exchange remains using ONIX 2.1. The time for change has now come though, at the minimum would be to for all publishers and data recipients to familiarize themselves with the changes. has a number of papers describing the changes as well as an overview document Best Practice Guidelines that explain both what needs to be recorded and why.

Implementation LISTSERV

Join Yahoo Groups ONIX_IMPLEMENT email list

Their archive of messages goes back beyond 2000 and covers a wide range of topics. Correct ONIX usage may be a matter of correctly matching code list definitions but it often depends on a consensus between suppliers and end users. This can vary between markets (each country has its own flavour of ONIX) and this forum is where the consensus begins.

Canadian-specific questions can be sent to and if necessary will be brought to the attention of the Bibliographic Committee (where Indigo is an active member).

Current ONIX Is Defined By:

Version 3.0 Revision 3

Version 2.1 Revision 03 (04 is largely about changes for Japan)

Code Lists Issue 37  (Codelists_Issue_37_Changes.pdf)

BISAC Subject Code list 2015 edition and Regional Themes 

Thema Version 1.2

The overview of ONIX for Books at the Editeur website.

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