E-invoice validator: check ZUGFeRD and XRechnung online

What the tool checks

You upload an XML file or a PDF with an XML inside. The tool works out the format and profile itself, then checks in three stages:

• Structure: Is every element in the right place, with the right data type? The XML schema of the syntax (CII or UBL) answers that.
• EN 16931 business rules: Mandatory fields such as invoice number, date, addresses and the VAT breakdown, plus the calculation rules for lines, VAT and the total.
• XRechnung rules: For an XRechnung, the German BR-DE rules apply on top, for example for the buyer reference, the seller's contact details and the payment details.

For a PDF, the tool takes out the embedded XML and checks exactly that. It also looks at whether the XML is linked to the PDF as an associated file. It does not check whether the PDF itself is a valid PDF/A-3 archive file. The rules are checked by the open-source library Mustangproject, the same library Rechnungskit uses to check its own invoices.

ZUGFeRD or XRechnung?

ZUGFeRD, called Factur-X in France, is a PDF with the invoice data inside as an XML file: people read the PDF, software reads the XML. XRechnung is a plain XML file with no visual part, mostly required by public-sector buyers. Both implement EN 16931 and count as an e-invoice under Section 14 UStG, ZUGFeRD from version 2.0.1 and without the MINIMUM and BASIC-WL profiles (Section 14.1(14) UStAE). More in our guides to ZUGFeRD and XRechnung.

Common errors and what they mean

• BR-DE-15, buyer reference missing: An XRechnung needs a buyer reference in field BT-10. For public authorities this is the Leitweg-ID, which the portal uses to route the invoice to the right office.
• BR-DE-6 and BR-DE-7, contact missing: XRechnung requires a seller contact with a phone number and an email address.
• BR-CO-15 and BR-CO-17, amounts don't add up: Net plus VAT must equal the gross total, and VAT is calculated per rate from the sum. If a shop rounds VAT per line, the result is often a cent off.
• BR-S-08, taxable amount doesn't match: Usually shipping costs or discounts are missing from the VAT breakdown of the matching rate.
• No e-invoice in the PDF: The PDF contains no XML with invoice data. Then it's an ordinary PDF invoice, even if it looks like a ZUGFeRD invoice.

Valid doesn't automatically mean correct

The check is purely technical. It tells you whether the file meets the standard and whether the amounts add up. No format check can judge whether the VAT rate fits your goods, whether an exemption applies or whether the supply happened as stated. That stays your call, together with your tax advisor if in doubt.

When you have to send e-invoices is covered in our guide to the e-invoicing mandate. Rechnungskit creates every invoice from Shopify, WooCommerce, Stripe or PayPal as ZUGFeRD in the EN 16931 profile and checks it with the same library before archiving it. See how that works on the pages about e-invoicing in Rechnungskit and e-invoicing software.