Automating E-Invoicing: How to Master the B2B Transition with XRechnung and ZUGFeRD
Automate e-invoicing: complete workflow from receipt through validation to GoBD-compliant archiving. With n8n, DATEV, and practical examples.
Since January 1, 2025, all domestic B2B companies are required to be able to receive e-invoices. Not someday, but now. And if you think a PDF invoice sent by email counts as an e-invoice, you are mistaken. This article shows the complete workflow: from the mailbox through validation and GoBD-compliant filing to handover to DATEV or an ERP system. Without developers, without chaos—with a system that works reliably even with 200 invoices per month.
What Has Applied Since January 1, 2025—and What Is Still Changing for Sending
The receiving requirement is clearly defined: according to the BMF, all domestic B2B companies have been required since January 1, 2025 to be able to receive structured e-invoices. A right to receive PDF or paper invoices in B2B no longer exists.
For sending, the situation is still somewhat more relaxed—but only temporarily. The transition periods are staggered:
- From 2027: Larger companies must send in structured format.
- From January 1, 2028: All companies must send in structured format.
- Exceptions: Small-amount invoices, transport tickets, and in some cases micro-enterprises—but these are exceptions, not the rule.
The clear recommendation: do not wait until 2028. Those who build their receiving and processing workflow properly now will save themselves the stress later and gain real time savings in the meantime.
E-Invoice vs. Other Invoice: What the Difference Costs
This point causes the most confusion in practice. A PDF invoice, even if it arrives by email, is not an e-invoice under current law. It is classified as an “other invoice.”
A genuine e-invoice is a structured, machine-readable format that enables a system to process the data directly without a person typing anything. That sounds technical, but it is the decisive difference: no manual data entry, no media breaks, no typing errors.
XRechnung vs. ZUGFeRD: The Two Standards Compared
Two formats dominate the German market, and both comply with the EU standard EN 16931:
XRechnung is pure XML. No PDF, no attractive layout. But 100 percent machine-readable and the preferred format for government agencies and public-sector clients.
ZUGFeRD is a hybrid format: a normal PDF with embedded XML. The recipient sees a readable invoice, while the system pulls the data from the XML part. Practical for the transition, because both humans and machines can work with it.
The crucial point: With ZUGFeRD, the XML part is authoritative. If the PDF and XML differ from each other, the XML applies. This has direct implications for archiving and auditing.
Typical Incoming Channels: Where the Invoices Arrive
In practice, e-invoices come in through four channels, depending on the company’s size and setup:
Email Mailbox
Still the most common channel for SMEs. A dedicated address (e.g., [email protected]) is set up, and the automation workflow monitors this mailbox via IMAP.
Peppol Network
Essentially the highway for structured invoices—standardized across Europe, primarily used in the B2G sector (government) and by larger companies.
DATEV E-Invoice Mailbox
A sensible option for everyone already using DATEV. According to DATEV, the mailbox is available free of charge until June 30, 2026, after which a pay-per-use model applies (receiving remains free, sending from third-party systems then costs approximately 0.50 euros per outgoing invoice).
Supplier Portals
For larger clients—invoices are uploaded manually or there is an API connection.
For most trade businesses and SMEs, the following is sufficient to start: a dedicated email mailbox plus DATEV integration. That covers 80 percent of cases.
Validation in Practice: What Needs to Be Checked
Before an invoice enters the system, it should pass through two verification stages:
Format Verification
Is the XML even valid? Does it conform to the EN 16931 schema? A validator checks this automatically in seconds.
Business Rule Verification
Are all mandatory fields populated? Are tax rates and amounts correct? Is the invoice number unique? The BMF explicitly recommends validation as a sensible process step, even though it is not a mandatory prerequisite for tax recognition.
Typical error categories from practice: missing tax ID, incorrect date format, tax amount inconsistent with net amount times tax rate. All solvable problems—but better to catch them before the handover to DATEV than after.
GoBD and Retention: What Must Be Archived
The GoBD requirements were recently updated to explicitly address structured e-invoices. What this means specifically:
- Original XML: Must be archived unchanged, machine-readable, and traceably. The XML must not be converted to another format and stored only in that form.
- ZUGFeRD PDF: Additionally retain if it contains tax-relevant information not found in the XML. In practice: usually archive both parts.
- Audit trail: Every booking needs an audit trail—who approved what and when, which validation steps the invoice went through.
- Retention period: 10 years for tax-relevant documents.
DATEV documents the legal requirements very clearly for deeper insights.
Automation Blueprint: n8n plus XML Parsing plus Human-in-the-Loop plus DATEV
Here is the workflow that has proven effective in practice:
Step 1: Receipt
n8n monitors the dedicated invoice mailbox via IMAP trigger. Every new email with an attachment triggers the workflow.
Step 2: Format Detection
Is the attachment an XML file (XRechnung) or a PDF with embedded XML (ZUGFeRD)? The XML part is extracted accordingly. Only if no structured format is present—meaning a plain PDF invoice—does AI-OCR come in as a fallback. XML-first, OCR only when necessary.
Step 3: Validation
Automatic verification against the EN 16931 schema and business rules. Errors are logged, and the invoice goes into an exception queue.
Step 4: Human-in-the-Loop
Exceptions (validation errors, unknown suppliers, unusual amounts) land in a review dashboard. A human decides—not blindly, but with all information at a glance.
Step 5: Handover
Validated invoices are handed over in structured form to DATEV or the ERP. No more manual typing.
Step 6: Archiving
XML (and PDF where applicable) are stored in an audit-proof DMS with timestamp, verification log, and booking reference.
According to DATEV, processing times for incoming invoices are reduced by up to 60 percent with this approach. The decisive point: the time savings come not from magical AI but from eliminating mindless manual work.
Practical Examples from the Mid-Market
Example 1: Timber Construction Company with 18 Employees
Before: One employee spent 1 to 2 hours daily manually entering invoices into DATEV, error rate never zero.
After: The same process runs automatically with n8n plus DATEV integration, human-in-the-loop only for genuine exceptions (approximately 5 to 10 percent of invoices). The employee was freed for other tasks.
Example 2: Furniture Design Studio (Solo plus Mini-Job)
Before: Clients sent XRechnung invoices, and the owner opened XML files with a text editor—without understanding the format.
After: After half a day of setup: dedicated invoice mailbox, ZUGFeRD viewer, n8n workflow for incoming invoices, GoBD-compliant filing in DMS. The format is understood and can be explained.
Checklist: Setup, Operations, Audit Readiness
Setup
- [ ] Dedicated invoice mailbox set up
- [ ] DATEV e-invoice mailbox activated (free until June 30, 2026)
- [ ] n8n workflow for receipt plus validation built
- [ ] Error queue and review dashboard defined
- [ ] DMS filing structure with original format established
Operations
- [ ] Weekly check of the exception queue
- [ ] Keep supplier mapping up to date
- [ ] Adjust validation rules after BMF updates
Audit Readiness
- [ ] XML archived in original format (unchanged)
- [ ] Audit trail available for every booking
- [ ] Retention periods observed (10 years for tax-relevant documents)
- [ ] GoBD documentation of the workflow available
Common Mistakes—and How to Avoid Them
Mistake 1: Treating PDF as an E-Invoice
Happens constantly. Solution: the workflow detects missing XML structure and flags automatically.
Mistake 2: Transforming XML Instead of Archiving
Anyone who converts the original XML into a different structure and only saves that has a GoBD problem. Always keep the original.
Mistake 3: Skipping Validation
“It comes from a reputable supplier anyway.” Until it does not. Validation takes seconds and saves hours in troubleshooting later.
Mistake 4: Forgetting Human-in-the-Loop
Fully automatic sounds great until a wrong invoice gets booked. A smart exception queue is not an admission of weakness but good system design.
Frequently Asked Questions
What is an e-invoice under the new legal framework?
An e-invoice is a structured, machine-readable document that conforms to the EU standard EN 16931—meaning XRechnung (pure XML) or ZUGFeRD (PDF with embedded XML). A regular PDF invoice sent by email does not count as an e-invoice in the legal sense.
What is the difference between XRechnung and ZUGFeRD?
XRechnung is pure XML, no visual document—exclusively for machines. ZUGFeRD combines a readable PDF with an embedded XML dataset. With ZUGFeRD, the XML part is legally authoritative.
As a micro-enterprise, do I have to issue e-invoices?
All domestic B2B companies must be able to receive e-invoices as of January 1, 2025. For issuing, there are partial exceptions for micro-enterprises and small-amount invoices. The exact conditions can be found in the BMF FAQ.
What do I need to consider for GoBD-compliant archiving?
The original XML must be retained unchanged, machine-readable, and with a complete audit trail. For ZUGFeRD, the PDF must additionally be archived if it contains tax-relevant information. Retention period: 10 years.
Can I use n8n for incoming invoice processing if I am not a developer?
Yes. n8n is a visual automation platform with drag-and-drop. There are ready-made workflow templates for IMAP receipt, XML parsing, and DATEV handover.
Conclusion: Act Now Instead of Panicking in 2028
Automating e-invoicing is not rocket science. The legal requirements have been clear since January 2025, the tools are available, and the workflow can be built in a manageable sprint. Think XML-first, validate, archive GoBD-compliantly, human-in-the-loop for exceptions—that is the recipe. Those who tackle this now will have a system that runs by 2028.