Verify before an invoice is sent or paid. One call checks net + VAT = gross, the...
https://agentshield.live/invoiceOverview
Verify before an invoice is sent or paid. One call checks net + VAT = gross, the VAT amount against the given or standard country rate, the IBAN checksum, the VAT id (German checksum or EU format), the date and the number, and flags the German 250 euro small-invoice rule. Returns ok plus each failed field. Not an XRechnung schema validation.