E-Invoice EN 16931 for WooCommerce — ZUGFeRD, Factur-X and XRechnung from your orders

E-Invoice EN 16931 for WooCommerce turns every order into an electronic invoice under the European standard EN 16931: ZUGFeRD / Factur-X (a PDF/A-3 with the XML embedded) and XRechnung 3.0 in the CII and UBL syntaxes — formats that both people (PDF) and software (XML) can read. The plugin does it inside WooCommerce — no external service, no subscription, and no order data handed to third parties.

Honestly about testing. The plugin went through a full run on WordPress 7.1 and WooCommerce 11.1 (classic and block checkout, HPOS on and off, real e-mail delivery): 25 of 25 XML files ACCEPTABLE in the official KoSIT 1.6.3 validator with the XRechnung 3.0.2 configuration, every PDF and factur-x.xml valid in Mustang 2.26 (EN 16931 and veraPDF PDF/A-3b), and the total of every document equals the order total. We have not tested real portals and software yet — ZRE / OZG-RE, Peppol, DATEV, lexoffice: try it on your own shop in the 7-day Pro trial. The tax content of the invoice (categories, exemption texts) is the seller’s settings, not tax advice.

What the customer sees

• A VAT number field (USt-IdNr.) for business customers — on the classic and block checkout. The number is normalised (“de 123 456 789” → DE123456789), and a clearly wrong format stops the order with a hint.
• Buyer reference / Leitweg-ID — an optional field for public-sector buyers; it goes into the invoice as BT-10, which XRechnung portals require.
• The invoice by e-mail (Pro): the PDF with embedded XML comes with WooCommerce’s order-completed e-mail, plus the XRechnung XML for orders with a Leitweg-ID.
• Invoices in My account (Pro): customers download their invoices and credit notes themselves, without writing to the shop.

What the admin gets

• E-invoice box in the order: issue the invoice, download the PDF, XML (CII), XRechnung CII or UBL, see credit notes and correct the buyer’s VAT ID or Leitweg-ID.
• Settings check against a real order: the plugin builds an invoice with your details and tells you what is missing for a valid ZUGFeRD and XRechnung, before the first real invoice. There is also an unnumbered sample PDF.
• VAT categories set automatically: standard rate S, reverse charge K / AE for a B2B customer from another EU country with a VAT ID, export G, small business under §19 UStG — E; each with a reason text and VATEX code. A product can have its own category set by hand.
• Gap-free numbering from a pattern like RE-{YYYY}-{N:5}, restarting every year and continuing from the last number of your previous tool. A number is never “lost” when the plugin is deleted and reinstalled.
• Payment: IBAN / BIC, days until due, terms text; the UNTDID 4461 payment means and a “Customer pays after the invoice” switch for every WooCommerce payment method.

Pro: automatic issuing, credit notes, customer account and a ZIP for the accountant

• Automatic issuing when the order reaches the chosen status, with the PDF in WooCommerce e-mails to the customer.
• Credit notes (Gutschrift, type 381) from refunds — line refunds and amount-only refunds, with their own numbering (GS-…) and a reference to the invoice. An amount-only refund is split over the invoice’s VAT groups proportionally — the credit note total is exact.
• ZIP for your accountant per period: all PDFs, XRechnung files and a CSV list (UTF-8 with BOM, opens in Excel with umlauts intact).
• VIES check of the VAT ID at checkout and your shop logo on the PDF.

Works together with our other modules for Germany and the EU

E-Invoice EN 16931 was built alongside three other modules of ours, and they have been tested together in one shop:

• EU VAT Check for WooCommerce checks the buyer’s VAT number in VIES and removes VAT under reverse charge — E-Invoice takes the verified number and sets categories K / AE. There is one VAT number field at checkout.
• DATEV Export for WooCommerce exports the postings for your tax adviser with the E-Invoice invoice number in the document field.
• Unit Price Grundpreis for WooCommerce shows the price per 1 kg / 1 l in the shop; invoices with such products pass the validators with unchanged line items.

How it works — step by step

1. Fill in the seller details (name, address, VAT ID or Steuernummer, contact) and payment details.
2. In “Check with order” pick any order — the plugin shows whether the invoice will be valid and what to add.
3. The customer places the order; a business customer enters a VAT ID, a public-sector buyer a Leitweg-ID.
4. You click “Issue invoice” in the order (with Pro the invoice is issued by itself at the chosen status and sent by e-mail).
5. A refund in WooCommerce → with Pro, a credit note referencing the invoice right away.
6. At month end — a ZIP with every invoice for your accountant, or an export with DATEV Export.

Under the hood

• Standards: EN 16931 (urn:cen.eu:en16931:2017), ZUGFeRD 2.5 / Factur-X 1.09 with XMP metadata and the factur-x.xml attachment (AFRelationship Alternative), XRechnung 3.0 (CustomizationID xrechnung_3.0) in CII and UBL.
• PDF/A-3b with an sRGB profile and embedded Liberation Sans fonts (OFL); characters outside the font print as “?” in the PDF and stay correct in the XML.
• Totals by the EN 16931 rules: VAT is calculated on the group base (BR-CO-17), and the difference to WooCommerce’s per-line rounding is closed with RoundingAmount — the amount due always equals the order total.
• File access is checked: customers download only their own documents; guests and other customers get 403.
• Numbering in separate counters that are kept on uninstall, as is the invoice metadata in orders — documents have to be retained by law.

Installation

1. Plugins → Add New → Upload Plugin: choose catcode-e-invoice-en-16931-for-woocommerce-1.0.0.zip and activate.
2. WooCommerce → E-Invoice: seller details, payment details, numbering, VAT categories.
3. “Check with order” — pick an order and make sure the invoice will be valid.
4. For Pro: paste the licence key from the e-mail after payment or start the 7-day trial, then choose the status for automatic issuing.