Validating CARF XML: the errors that get filings rejected

Identifier collisions

Each message and each record carries unique references, a MessageRefId for the file and a DocRefId for every document inside it. Reuse one across submissions, or duplicate one within a file, and the schema rejects the whole thing. Corrections make this sharper still: an amendment has to point back at the exact DocRefId it replaces, so sloppy identifier hygiene breaks not just the first filing but every fix after it.

TIN and country-code problems

A taxpayer identification number that doesn't match the expected format, or a residence country code that isn't a valid ISO entry, is one of the most common rejection reasons. This is why the format check belongs at onboarding, not at filing, a point we make in the CARF self-certification and TIN validation workflow.

Message-type and structural mismatches

The schema expects the file to declare what it is, a new report, a correction, a nil return, through the MessageTypeIndic and related fields, and the body has to match that declaration. Mixing new and corrected records incorrectly, or leaving a required element empty, fails the XSD even when every number is right.

Version drift

The CARF XML schema has versions, and jurisdictions move to new ones on their own timelines. A file built to last year's schema, or to the OECD baseline where a country requires its own national envelope, gets rejected on arrival even though it's technically valid CARF. Sweden's KU94 is the classic example of a national format a generic build doesn't produce.

Catching it before submission

The fix is to validate hard, before anything leaves the building, against the exact schema each authority accepts. Our CARF and DAC8 reporting platform runs a multi-tier XSD gate on every file and generates the national envelopes, not just the OECD baseline, so a filing doesn't bounce on a structural error you could have caught. The blocking and cure-period side of compliance is covered in the CARF 60-day rule, and the OECD exchange-of-information hub publishes the schema and user guide.