German B2B e-invoicing is moving from optional to mandatory. Since January 2025 every domestic B2B recipient must be able to receive structured e-invoices, and issuing obligations phase in through 2027-2028 based on company turnover. ERPNext core prints a clean PDF and can email it, but a human-readable PDF is not a structured e-invoice — it carries no embedded XML, no EN 16931 semantic model, no BT/BG business terms, and nothing a Leitweg-ID-driven public buyer or a Peppol Access Point can machine-read. Teams running ERPNext in Germany hit this wall the moment a customer asks for XRechnung or a ZUGFeRD-compliant document, and the standard Sales Invoice print format simply cannot satisfy it.

We build a proper Frappe app that plugs directly into your existing Sales Invoice flow. On submit, a hooks.py doc event (on_submit / on_update_after_submit) invokes a server-side generator that maps ERPNext fields — company tax IDs, customer address, Sales Taxes and Charges, item lines, UoM, and payment terms — into an EN 16931-conformant document. The app produces both target formats from one data model: XRechnung as pure structured XML in either UBL 2.1 or UN/CEFACT CII syntax, and ZUGFeRD as a PDF/A-3 file with the CII XML embedded as an attachment for hybrid human-plus-machine consumption. A dedicated E-Invoice DocType tracks each generated document, its profile (XRechnung / ZUGFeRD / EN 16931 comfort level), validation status, Leitweg-ID for public-sector buyers, and the transmission log.

Delivery is built to your channel. We wire optional Peppol dispatch through your chosen Access Point (or a certified partner), record the transmission ID and acknowledgements back onto the E-Invoice record, and expose whitelisted REST methods (@frappe.whitelist()) so upstream systems or the Frappe REST API can trigger generation and pull document status. Client scripts add validate/preview/download actions to the Sales Invoice form; role profiles and permission rules keep issuance and re-transmission scoped to finance roles; and a scheduler event handles ret/backoff on failed Peppol sends and can batch-validate open documents. We support ERPNext / Frappe v15 and v16 and pin the exact framework version at scoping.

Because this is build-to-order, nothing ships until we agree on scope. We start with a short scoping call, confirm your formats (XRechnung UBL vs CII, ZUGFeRD profile), your Peppol path, and your edge cases (reverse-charge, intra-community supply, credit notes), then build on a staging bench. Typical delivery is one working week from confirmed scope. You receive the installable source, install and configuration on your environment, UAT on staging with a rollback plan, documentation, a training session, and a post-go-live support window. This is not an instant marketplace download — it is a scoped app we build, install, and stand behind.