- Who it's for
- Finance and IT teams in mid-sized companies where invoices arrive by email, through portals and via EDI.
- What you'll be able to do
- Plan intake, validation, approval and archiving as one flow, and decide whether to build it yourself or buy it.
- As of
- February 2026
E‑invoicing can be fixed pragmatically: centralized intake, validation, approvals, and auditable archiving. Don’t turn it into a massive ERP project — build a small internal app that stays cleanly auditable.
The legal baseline (primary sources)
From 2025‑01‑01, e‑invoices are mandatory in German B2B transactions, accompanied by transition provisions. An e‑invoice means a structured electronic format that enables electronic processing (e.g. EN 16931). You can read it up on the federal info page and in the FAQ of the German Ministry of Finance, which also hosts the official documents.
Not legal advice. Use the BMF docs / your tax advisor for binding interpretation.
The real problem: the invoice isn’t the bottleneck — the workflow is
The typical reality in 2026: invoices arrive via email, portals and EDI, all fragmented. Approvals happen in chat tools and hallway conversations. Evidence is scattered and audit trails are weak. And accounting ends up doing the manual reconciliation.
Target state: a lean, enforceable process that’s provably auditable.
A minimal setup that actually works
You need four building blocks.
- 01Inbox and intakeA dedicated email alias, portal downloads and, if needed, EDI — all imported automatically into one system.
- 02Validation and risk checksFormat, schema, mandatory fields, VAT rates, IBAN, vendor match and duplicates. Anything unusual gets flagged.
- 03Approval workflowOwnership follows the cost center or project, anything above a set threshold needs two steps, and a reminder goes out when a deadline slips.
- 04Archive and exportDocument and structured data archived compliantly, export into ERP, DATEV or accounting, plus the audit trail.
Validation and risk checks: format and schema are validated (XRechnung, ZUGFeRD, EN 16931), and so are mandatory fields, VAT rates, IBAN, vendor match and duplicates. Anything unusual gets flagged — a new vendor, say, or a spike in the amount.
Why a small internal app is often the sweet spot
A lightweight internal app beats “let’s contort the ERP” whenever you have multiple intake channels (email, portal, EDI), whenever you need strict approvals instead of just booking, whenever you need a clean audit trail — or whenever your ERP is good at posting but bad at controlling workflows.
The app itself can stay simple: a UI showing the inbox with statuses (new, in review, approved, posted), rules for validation and routing, and integrations with email, storage and ERP or DATEV.
Checklist 1: Operational compliance basics
- Central intake + defined import (no lost invoices in inboxes)
- Structured data validation (schema + mandatory fields)
- Clear approval rules (thresholds, owners, delegation)
- Compliant archiving + unique document IDs
- Auditability: event trail (who/what/when)
- ERP/accounting export including structured data
Checklist 2: Build vs buy (pragmatic)
- More than one intake channel (email/portal/EDI)? → integration layer helps
- Need approvals by cost center/project? → workflow layer required
- Many exceptions (credit notes, partial deliveries, discounts)? → rules + UI
- Is “posting” enough, or do you need “control + evidence”? → audit trail
- Monthly volume? → set automation level accordingly
A realistic 14‑day plan
- Days 1–2: map intake channels + approval rules + export target
- Days 3–5: intake + storage + baseline validation
- Days 6–9: approvals + roles + reminders
- Days 10–12: ERP/DATEV export + duplicate logic
- Days 13–14: audit trail + tests + 1‑page SOP
Getting the internal e‑invoicing app built
Send me:
- Your ERP/accounting stack (DATEV, SAP, Navision, …)
- How invoices arrive (email/portal/EDI)
- Who approves what (roles + thresholds)
I’ll propose a small internal app that imports, validates, routes, and archives e‑invoices with a clean audit trail.