Fuchs_Intranet/Fuchs/Docs/Concepts/erechnung-output.md

status, lastUpdated, applyTo, relatedDecisions

status	lastUpdated	applyTo	relatedDecisions
Active	2026-07-18	Fuchs/Services/ERechnungMapper.cs Fuchs/Services/ERechnungService.cs Fuchs/Services/ERechnungSettings.cs Fuchs/Services/InvoiceRecipientAddress.cs Fuchs/Services/InvoiceService.cs Fuchs/code/FuchsPdf.cs eRechnungLib/**	0005-pdf-generation-and-erechnung.md 0012-erechnung-single-pdfa-engine-pipeline.md

eRechnung output (ZUGFeRD/Factur-X)

Summary

Finalized invoices are emitted as a ZUGFeRD 2.4 / Factur-X hybrid: the FuchsPdf visual PDF with the EN 16931 CII XML embedded, in a formally conformant PDF/A-3. This makes invoices DATEV-ingestible and satisfies the B2B/B2G e-invoicing mandate. The library doing the structured XML + PDF/A-3 work is the eRechnungLib submodule; Fuchs supplies the invoice data and the visual PDF.

How it works

Editor (structured recipient dialog)
   → InvoiceDraftEditService  (address delta = JSON object, stored in CustomValues.sendToAddress)
   → fds__setInvoice/…        (persisted; dedicated SendToAddressJson column + composed SendToAddress)
   → InvoiceService.RenderInvoicePdfBytesAsync(final)
        ├─ FuchsPdf.DocToPdfBytesRaw(doc)          → visual PDF (no Spire PDF/A)
        └─ IERechnungService.TryBuildHybridPdf
               ├─ ERechnungMapper.BuildEInvoice     FdsInvoiceData → eRechnungLib.Model.Invoice
               └─ EInvoice.ToZugferd(EN16931, raw)  → PDF/A-3 + Factur-X hybrid (bundled sRGB ICC)

• Single PDF/A engine (ADR 0012). eRechnungLib owns the one PDF/A-3 layer. For the eRechnung path the Spire PDF/A step is skipped (DocToPdfBytesRaw); Spire stays only for on-screen preview rasterisation. This avoids a conflicting second output intent / pdfaid marker.
• Structured recipient address. InvoiceRecipientAddress holds the EN 16931 buyer fields (name, street, post code, city, country BT-55, optional VAT id BT-48). It is edited via a dialog form ($inv.eAddress in fis.inv_shared.js), prefilled from fds__prepInvoice's invoiceaddressData, and carried as a JSON object through the draft cache. A private person (no VAT id) is fully valid — B2C stays effortless. The free-text SendToAddress is composed from it so the PDF layout is unchanged.
• Mapping. ERechnungMapper maps the Fuchs invoice to the EN 16931 model: seller = Fuchs (constants mirroring the FuchsPdf letterhead — name, Steuernummer BT-32, IBAN/BIC), buyer = the structured recipient, lines from the invoice items, §13b → reverse charge (category AE + exemption reason). VAT breakdown and totals are recomputed by the library.
• Feature flag & fallback. Emission is gated by Fuchs:ERechnung:Enabled (off until fully validated). IERechnungService returns null on disable or any failure, so RenderInvoicePdfBytesAsync falls back to the plain Spire PDF/A — invoicing never breaks.
• Formal verification. Fuchs:ERechnung:Validation:ServiceUrl is the seam for an external online veraPDF (PDF/A-3) + ZUGFeRD validator; until the URL is provisioned, verification is reported as not-configured.

Key files

• Fuchs/Services/InvoiceRecipientAddress.cs — structured buyer address, composition, conformity.
• Fuchs/Services/ERechnungMapper.cs — FdsInvoiceData → eRechnungLib.Model.Invoice.
• Fuchs/Services/ERechnungService.cs / ERechnungSettings.cs — hybrid production + config.
• Fuchs/Services/InvoiceService.cs — wiring in RenderInvoicePdfBytesAsync.
• Fuchs/code/FuchsPdf.cs — DocToPdfBytesRaw (render-only visual PDF).
• Fuchs/js/intranet/modules/fis.inv_shared.js — $inv.eAddress structured dialog.
• Fuchs_Database — fds__invoices.SendToAddressJson, fds__getCompanyAddressJson, fds__prepInvoice.invoiceaddressData, fds__createInvoice/setInvoice/getInvoice.
• eRechnungLib/** — CII/UBL serialization, EN 16931 validation, FacturXPdfBuilder (PDF/A-3).

Related decisions

• 0005-pdf-generation-and-erechnung.md
• 0012-erechnung-single-pdfa-engine-pipeline.md