From 1 January 2027, issuing e-invoices becomes mandatory for German companies with prior-year revenue above €800k, and from 2028 for everyone. Unlike receiving, this cannot be ticked off with an inbox: the invoice has to leave your system as structured data under EN 16931 (as XRechnung or ZUGFeRD) and be machine-processable on the recipient’s side.
I make sure outgoing invoices are generated and transmitted compliantly straight from the ERP, without manual steps in between. The 2027 readiness check shows how far your company is from that point.
Compliant generation from the ERP
Printing a PDF and converting it afterwards is not a solution. The structured data has to be correct where the invoice is created: in the ERP, with clean master data and complete mandatory fields. Validation before sending catches wrong tax categories or country codes before the recipient’s import does, sparing you the correction ping-pong.
Real-time export with a posting matrix
The DATEV integration whitepaper documents the export of outgoing invoices as real-time transfer of posting batches, including a configurable Buchungsmatrix: a posting matrix spanning four dimensions. The posting is created in the same step as the invoice, not during a month-end export. The matrix itself is explained on the account assignment page.
Special cases: down payments, installments, cancellations
The standard case is rarely the problem. Project-driven companies work with down-payment and installment invoices, and that is exactly where many e-invoicing rollouts break. The two whitepapers document the implemented logic: down-payment invoices with a full lifecycle from creation through successive clearing to final settlement, FIFO ordering when a project carries several down payments (with safeguards against over-clearing), installment invoices booked via an interim account until the final invoice, and cancellations. Discovering these cases in live operation means building workarounds that have to survive a tax audit.
The full path from document to finalized posting batch is laid out on the E-Invoicing & DATEV overview.