Identify the correct receiving portal for your federal or state contracting authority; OZG-RE (the Onlinezugangsgesetz-konforme Rechnungseingangsplattform) replaced ZRE in September 2025 and is the primary federal portal — individual states may operate their own conformant portals.
Obtain the Leitweg-ID (routing identifier) for the contracting authority from the contract or purchase order; this identifier must appear in the BuyerReference field of the XRechnung document.
Generate a valid XRechnung 3.0 XML document (UBL 2.1 or CII syntax) conforming to the CIUS-DE specification; validate against the official Schematron rules before submission — OZG-RE accepts only well-formed XRechnung, not PDF.
Submit the invoice via one of the accepted channels: XML upload through the OZG-RE web portal, email transmission to the portal address listed on the contract, or Peppol network delivery using your access point.
Monitor the portal or your Peppol access point for processing status; OZG-RE will return a technical acknowledgement and, if accepted, forward the invoice to the contracting authority's ERP.
Retain the submission confirmation and any processing receipt for audit; German public procurement law requires the ability to demonstrate timely invoice delivery.
Known gotchas
ZRE has been replaced by OZG-RE as of September 2025 — do not submit to the old ZRE endpoint or portal address; existing ZRE integrations must be migrated.
The Leitweg-ID is mandatory and must match exactly the identifier in the contract; a missing or mismatched Leitweg-ID will cause the invoice to be rejected without reaching the contracting authority.
XRechnung 4.0 (released in 2026) introduces multi-delivery and multi-payment-term fields aligned with Peppol BIS 4.0 — check which version your contracting authority's portal accepts before upgrading your templates.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp