E-invoice formats compared XRechnung, ZUGFeRD, Factur-X, Peppol BIS, UBL and CII compared, plus an overview of the EN 16931 standard. XRechnung vs ZUGFeRD: the difference and which format to choose Factur-X vs ZUGFeRD: one format, two names XRechnung vs Peppol BIS: format and transmission UBL vs CII: the two XML syntaxes of EN 16931 EN 16931: an overview of the European e-invoicing standard