Free ONIX File Validator — Check ONIX 2.1, 3.0 & 3.1
Check Your Book Metadata Online
Built for publishing editors and metadata managers, this free tool validates ONIX XML against the EDItEUR schemas bundled with onixcheck. It groups repeated problems, identifies affected records when possible, and explains how to repair them in plain publishing language.
Free ONIX file check
Drag your ONIX file here
No sign-up required.
Supported file types: .xml, .onx, and .onix · Maximum file size: 5 MB.
Your file is uploaded over HTTPS, processed temporarily on the validation service, and deleted after validation. Privacy details
What is ONIX?
ONIX for Books is the international standard XML format for communicating book product metadata. Maintained by EDItEUR, it defines a precise vocabulary for describing titles, contributors, identifiers, prices, territorial rights, and supporting resources so that trading partners can exchange catalog data without manual re-keying.
Publishers create ONIX messages; distributors, wholesalers, retailers, and library suppliers receive them. A message contains a header and one or more product records, each describing a sellable edition or format through identifiers, titles, subjects, descriptions, prices, rights, and supply terms.
Because the format is strict, a misplaced element or invalid code can prevent a record or feed from loading. Validation finds those problems before a trading partner processes the file.
This validator supports the obsolete but still encountered ONIX 2.1 release as well as ONIX 3.0 and 3.1, in both reference-tag and short-tag formats.
Common ONIX Errors We Catch
Schema validation errors. The file breaks the official ONIX specification: unexpected or misspelled elements, elements in the wrong order, missing required elements or composites, and values that violate the format the schema requires (for example a malformed publication date).
Invalid code-list values. ONIX fields such as product form, contributor role, and price type draw from EDItEUR code lists. An invalid or obsolete value may be rejected or interpreted incorrectly.
ISBN and identifier problems. Our project quality rules flag records with no usable product identifier, ISBNs that fail check-digit rules, and duplicate record references — issues that can pass schema validation but disrupt downstream updates.
Metadata-quality warnings. Clearly separated from official schema errors, these recommendations cover problems like missing titles, contributors without roles, and prices without currencies — problems that can lead to incomplete or incorrect product data.
How the Validator Works
- Upload. Drag your ONIX file into the box above or choose it from your computer. The file is sent over HTTPS to the validation service.
- Review. The workspace shows grouped problem types, your original XML, and repair guidance side by side. Select an issue and use Locate in source to highlight its reported position.
- Repair and re-check. Follow the repair steps in your source system, export a corrected file, and validate again until the report is clean.
Supported Versions and Limitations
Validation uses the ONIX 2.1, 3.0, and 3.1 XML Schemas bundled with the pinned onixcheck 0.9.11 engine. Every report shows the engine version and detected ONIX release.
A schema-valid file is not guaranteed to be accepted by Amazon, Ingram, Google, or any other channel because recipients apply additional rules. The tool cannot confirm that business data is accurate or complete, and project warnings are recommendations rather than official ONIX errors.
Frequently Asked Questions
What is an ONIX validator?
An ONIX validator checks whether an ONIX for Books XML file follows the official EDItEUR schema. It finds structural errors, missing required elements, and invalid code values, and — in this tool — explains each problem in publishing language with repair steps.
Which ONIX versions are supported?
The validator supports ONIX 2.1, ONIX 3.0, and ONIX 3.1, in both reference-tag and short-tag formats, validated against the official XSD schemas bundled with onixcheck 0.9.11.
Is my ONIX file uploaded to a server?
Yes. The file is uploaded over HTTPS so the onixcheck engine and our quality rules can run on it. The file is held only in an isolated temporary location on the validation server while your request is processed.
How long is my file stored?
Your file exists only for the duration of the validation request. This service does not intentionally save uploaded XML files or validation history after processing completes.
What is the difference between an error and a warning?
Errors identify XML, schema, or project-rule failures that can block reliable processing. Warnings flag metadata-quality risks. Project recommendations are clearly separated from official validator findings.
Does a valid ONIX file guarantee retailer acceptance?
No. Schema-valid means the file conforms to the official ONIX specification. Retailers and distributors apply their own additional requirements, so a schema-valid file can still be rejected by a specific channel.
Can the tool fix my ONIX file automatically?
Today the validator explains each problem and tells you how to repair it — it never silently changes your metadata. A future version may offer a small set of safe, mechanical fixes with a visible diff and your explicit approval before anything changes.
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