ONIX (Online Information Exchange) for Books is the dominant international standard for communicating product metadata in the book supply chain. Maintained by EDItEUR, the international standards body for the book and serials trade, ONIX enables publishers, distributors, wholesalers, retailers, and libraries to exchange rich, structured information about books and related products in XML format.
Background
ONIX for Books emerged in 2000 from a joint initiative by EDItEUR, Book Industry Communication (BIC) in the UK, and the Book Industry Study Group (BISG) in the United States. The original impetus was the growth of online bookselling, which created an urgent need for standardized product metadata that could be shared electronically between trading partners. Before ONIX, publishers transmitted product information through proprietary formats, spreadsheets, and printed catalogs, leading to inconsistency and data loss across the supply chain.
Release 2.1 became the most widely deployed version through the 2000s and 2010s. Release 3.0, a major restructuring with improved support for digital products and global markets, was published in 2009. Release 3.1 followed with incremental updates. The standard is now governed by an International Steering Committee with national user groups in over fifteen countries.
Purpose & Scope
ONIX for Books provides a comprehensive vocabulary for describing every aspect of a book product that a trading partner might need: bibliographic data (title, contributor, subject), commercial data (price, availability, distribution rights), physical description (format, extent, dimensions), and digital product characteristics (DRM, file formats, accessibility features). A single ONIX message can carry records for one or many products, and each product record can describe complex structures such as multi-volume sets, bundles, and products available in multiple formats.
The standard is not limited to print books. ONIX 3.0 and 3.1 support e-books, audiobooks, print-on-demand products, and related non-book items sold through book trade channels.
Key Components
ONIX messages are structured around the Product record, which contains composites organized into groups:
| Group | Content |
|---|---|
| Product Identifiers | ISBN, GTIN, proprietary identifiers |
| Descriptive Detail | Title, contributors, subjects (BISAC, BIC, Thema), audience, language, extent |
| Collateral Detail | Descriptions, reviews, cover images, supporting resources |
| Publishing Detail | Publisher, imprint, publication date, sales rights, territorial rights |
| Related Products | Replacements, alternatives, parts of a set |
| Product Supply | Availability, suppliers, prices by territory and currency |
EDItEUR maintains an extensive set of code lists (over 250) that define the controlled values used throughout ONIX messages.
Serializations & Technical Formats
ONIX is expressed exclusively in XML. EDItEUR provides XSD and DTD schema definitions for validation. Messages typically use either a short tag or a reference tag naming convention. There is no official RDF or JSON serialization, though some implementations convert ONIX data into other formats internally.
Governance & Maintenance
EDItEUR maintains the ONIX standards under the guidance of international steering committees. National user groups provide input on requirements and adoption. EDItEUR publishes code list updates on a regular cycle and maintains backward compatibility where feasible. The standard is made available through EDItEUR's website, with schema files, code lists, and documentation downloadable from the Release 3.0 and 3.1 downloads page.
Notable Implementations
ONIX for Books is used by virtually every major publisher worldwide and is required by many major retailers and aggregators:
- Amazon, Google Books, Apple Books: Require or strongly prefer ONIX feeds for product data ingestion.
- Nielsen BookData, Bowker: Use ONIX as the primary format for bibliographic data services.
- National libraries and library suppliers: Use ONIX for acquisitions and cataloging workflows, often in conjunction with MARC21 (EDItEUR publishes an ONIX-to-MARC21 mapping).
- Independent publishers: Increasingly use ONIX through metadata management platforms such as BookNet Canada's BNC CataList and similar national services.
Related Standards
- MARC21: Library cataloging format; EDItEUR provides a documented mapping between ONIX and MARC21.
- Thema: EDItEUR's international subject classification scheme, designed to work with ONIX.
- BISAC / BIC: National subject classification schemes widely used in ONIX records.