What is Schematron validation?
Short answer
Schematron validation is a rule-based check of an XML document. It is used to validate conditions that cannot be adequately expressed or practically checked using only an XSD schema. Schematron is a standardized language for rules
"This element exists"
XSD only checks the presence and shape of the element — not whether it makes sense.
"The sum must add up"
For example: TaxInclusiveAmount = TaxExclusiveAmount + TaxAmount. Or: if InvoiceTypeCode = 380, there must be other mandatory data — XSD doesn't know that.
How to read an error
BR = Business Rule, CO = Calculation — e.g. BR-CO-10, BR-CO-15. PEPPOL-EN16931-Rxxx are rules specific to the Peppol profile.
Local validation rules
Slovak transpositions and validation rules can add additional controls over the general Peppol framework.
Conclusion
Schematron validation is a regular check of XML e-invoice based mainly on XPath expressions.
Act No. 222/2004 Z. z. Coll. about VAT · FAQ of the Financial Administration of the Slovak Republic from 7 July 2026 · Peppol BIS Billing 3.0
Not legal advice. Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.