NormAPI – German e-invoices (XRechnung, ZUGFeRD)

NormAPI checks and creates German e-invoices from inside Claude. • validate_invoice runs the official KoSIT validator on an XRechnung (UBL or CII XML) or a ZUGFeRD / Factur-X PDF. It returns the verdict, the rule-set version and every finding. Each business-rule finding says what the rule requires, why invoices typically break it and how to fix it. • explain_rule explains any rule code that a rejection quotes, such as BR-DE-15, BR-CO-10 or PEPPOL-EN16931-R010. • parse_invoice reads a received e-invoice into structured data: parties, lines, totals and the VAT breakdown as the document states them, plus a list of every value it could not map. • generate_invoice builds an XRechnung (UBL or CII), a plain EN 16931 invoice for a business customer, or a ZUGFeRD PDF from invoice data. Totals are computed in decimal arithmetic, and the document is validated against the official rules before it is returned. Data the rules do not permit is refused, with the broken rules and how to fix each. Validation, parsing and rule lookups need no account. Generating uses the user's NormAPI account, with sign-in by email link. Invoices are processed in memory and never stored. Explanations come in English or German. This is technical validation against EN 16931 and the German XRechnung rules, not tax or legal advice.