E-Invoicing (E-Rechnung)

German e-invoicing support: emit EN 16931-compliant e-invoices, deliver them by email, and receive incoming e-invoices from suppliers. In Germany, receiving e-invoices has been mandatory for all businesses since 1 January 2025; sending becomes mandatory in 2027 (businesses above €800k) and 2028 (all businesses).

Opt-in module

E-Rechnung is disabled by default and invisible unless you turn it on — non-German users never see the E-Rechnung UI. Enable it under Settings → E-Rechnung (e-invoice):

• Shows the E-Rechnung panel on every invoice detail view
• Adds the E-Rechnungen inbox to the sidebar (/einvoices)
• Shows the E-Rechnung section in the customer form
• Enables auto-attaching the e-invoice to sent invoice emails
• The setting applies immediately after saving, no restart needed

Formats

Format	When it is used	Output
ZUGFeRD 2.2 (Factur-X)	Default (zugferd)	CII XML embedded in a PDF/A-3 hybrid PDF
XRechnung 3.0 (UBL)	Customer has a Leitweg-ID, or format set to xrechnung	UBL 2.1 XML (no hybrid PDF)
PEPPOL BIS 3.0	Customer or business format set to peppol	UBL XML

Resolution order per invoice: customer format → business setting → ZUGFeRD; a customer Leitweg-ID always forces XRechnung.

Company requirements

For a valid e-invoice your Settings must contain:

• Company name and address
• Either a VAT ID (DE + 9 digits) or a Steuernummer in German format (e.g. 12/345/67890), plus the country set to DE
• Optional: E-Rechnung default format and the Kleinunternehmer (§19 UStG) toggle, which emits reverse-charge-style zero-VAT documents

Missing or malformed fields do not block emission but are reported as validation errors/warnings in the emit response and shown in the panel.

Customer e-invoice fields

In the customer form (visible when the module is enabled):

Field	Purpose
E-invoice format	Overrides the business default for this customer
Tax number (Steuernummer)	The customer's German tax number, used as buyer tax number
Leitweg-ID	Official ID for public-sector (B2G) customers — forces XRechnung
Receiver ID / scheme	Identifier for XRechnung/PEPPOL delivery, e.g. DE:VAT, 0204

Emitting an e-invoice

1. Open the invoice → E-invoices (E-Rechnung) panel → Emit.
2. The invoice is validated against EN 16931 business rules; the XML (and hybrid PDF for ZUGFeRD) is generated and stored as an immutable revision.
3. Download the XML or hybrid PDF from the panel.

Via API

POST /api/v1/invoices/:id/einvoice/emit
GET  /api/v1/invoices/:id/einvoices
GET  /api/v1/invoices/:id/einvoices/:recordId/xml
GET  /api/v1/invoices/:id/einvoices/:recordId/pdf
DELETE /api/v1/invoices/:id/einvoices/:recordId

Sending by email

When the module is enabled, Send on an invoice emits the e-invoice and attaches it to the email automatically: a ZUGFeRD hybrid PDF for zugferd, the raw XML for XRechnung. Per-email control lives in the send dialog (Advanced → "Attach e-invoice"), and the global switch is the module toggle itself.

Inbox (receiving)

The E-Rechnungen page (/einvoices) is a mailbox for incoming e-invoices:

• Import — upload XRechnung (UBL) or ZUGFeRD (CII) XML files; duplicates (sha256) are rejected
• Parse — supplier, document number, issue date and total are extracted automatically
• Link — optionally link a document to a customer in your address book
• Status — move documents through inbox → processed → archived
• Raw download — keep the original file for tax archives (8 years, §147 AO)

Via API

GET    /api/v1/einvoices/inbox
POST   /api/v1/einvoices/inbox/import          (multipart, max 20 MB)
GET    /api/v1/einvoices/inbox/:id
GET    /api/v1/einvoices/inbox/:id/raw
POST   /api/v1/einvoices/inbox/:id/link        ({ customer_id })
POST   /api/v1/einvoices/inbox/:id/status      ({ status: inbox|processed|archived })
DELETE /api/v1/einvoices/inbox/:id

Storage & retention

• Emitted revisions are stored in einvoice_documents (XML + optional PDF + sha256 hash).
• Incoming files are stored in einvoice_inbox with their original bytes.
• Deleting an emitted revision is possible but not recommended — e-invoices must be kept for tax purposes for 8 years (§147 AO).