A VAT breakdown of category E (exempt) must contain an exemption reason as text (BT-120) or code (BT-121, VATEX).
UBL: <cbc:TaxExemptionReason> or <cbc:TaxExemptionReasonCode> in the TaxCategory. CII: ram:ExemptionReason(-Code) in ApplicableTradeTax.
The Billhorse validator checks XRechnung, ZUGFeRD and Factur-X right in your browser — your file is never uploaded.
Open the validator ← All validation rules
Rule source: EN 16931 / XRechnung (KOSIT) or Billhorse check (BH-*).