E-Invoice Mandate: One Year In
Since January 1, 2025, the e-invoice receiving obligation has been in effect for B2B transactions in Germany — and by extension, for Austrian companies doing business with German partners. After over a year of production use, here are the key lessons learned.
The timeline:
- Since January 2025: Receiving obligation — all companies must accept e-invoices ✅
- From January 2027: Sending obligation for companies over €800k revenue
- From January 2028: Sending obligation for all companies
Important for Austrian companies:
If you exchange invoices with German B2B partners, you're affected. Those who haven't switched yet should act now — the sending obligation is approaching fast.
The 5 Biggest Lessons Learned
1. ZUGFeRD Emerged as the Practical Winner
After a year, the verdict is clear: ZUGFeRD/Factur-X is the format of choice for most companies. It combines PDF (for humans) with XML (for machines) in a single file.
Why it works:
- Existing customers can still open invoices as regular PDFs
- Automated systems read the embedded XML data
- Eases the transition — both worlds in one file
Pro tip: Factur-X is the international version of ZUGFeRD 2.x and 100% compatible. We run ZUGFeRD 2.3 in production.
2. Master Data Quality Was the Biggest Hurdle
Technical implementation was rarely the main challenge. The real obstacle: clean master data.
Common problems:
- Missing or incorrect VAT IDs
- Inconsistent address data between ERP and reality
- Missing GLN numbers for PEPPOL transmission
- Wrong bank details in master data
Our approach: Master data cleanup as the first project step — before writing a single line of code.
3. Validation Is Mandatory, Not Optional
Invalid e-invoices get rejected. We learned that a robust validation pipeline is essential:
- Schema validation (XSD) as the first layer
- Schematron rules for business logic checks
- Testing with real recipients before go-live
- Monitoring for rejected invoices in production
4. The Three Formats in Practice
| Format | Use Case | Strengths | Weaknesses |
|---|---|---|---|
| ZUGFeRD/Factur-X | General B2B | Hybrid (PDF+XML), easy adoption | Larger file sizes |
| XRechnung | Public sector | Pure XML, compact | Requires special software to view |
| ebInterface | Austrian authorities | Established in AT | Less international |
Recommendation: Start with ZUGFeRD. Add XRechnung if you supply public entities. ebInterface only when explicitly required.
5. Integration Is the Key to ROI
An e-invoice that's manually exported from ERP and sent via email saves little. Real value comes from full integration:
- ERP → E-invoice generator (automatic on invoice creation)
- Validation (automatic before sending)
- Transmission (automatic via email or PEPPOL)
- Archiving (automatic with 7+ year retention)
- Monitoring (dashboard for rejected invoices)
What to Do Now
Haven't switched yet?
The receiving obligation is already in effect. The sending obligation comes in 2027/2028. Now is the time:
- Analyze: Which formats do your customers need?
- Master data: Clean up your data now
- Pilot: Start with one format and a few customers
- Roll out: Gradually expand to all customers
Already compliant?
Optimize:
- Set up monitoring for rejected invoices
- Increase automation level
- Prepare for the 2027 sending obligation
Conclusion
The e-invoice mandate was a challenge for many companies — but also an opportunity. Those who invest now benefit from more efficient processes, fewer errors, and lower costs. The technology is mature, the standards are clear. All that's left is implementation.