By Martin Dutzler, Senior Product Manager E-Invoice at fiskaly
The E-Rechnungsgipfel in Berlin last week gathered the people building, advising on, and adopting e-invoicing across Germany. And beneath the panels and hallway conversations, one uncomfortable truth kept surfacing: everyone understands the mandate, but far too few companies have actually started moving.
That gap between awareness and action is the story of German e-invoicing right now. Here is what Berlin made clear — and why the decisions companies make in the next twelve months will determine whether the mandate becomes a manageable transition or a scramble.
The market has to move — and the runway is shorter than it looks
Structured e-invoicing still accounts for only about 25–30% of B2B invoice volume in Germany. That number should give everyone pause, because the timeline set by the Wachstumschancengesetz is not a distant horizon. It is already underway:
- January 2025 — receiving e-invoices became mandatory for all businesses. This obligation is in force today.
- January 2027 — issuing becomes mandatory for companies with turnover above €800,000.
- January 2028 — issuing becomes mandatory for everyone else.
Read that first line again. Every German business is already legally required to receive structured e-invoices. The question is no longer whether to deal with e-invoicing but how well — and the issuing deadlines are now measured in months, not years.
Europe has seen this movie before. Belgium's rollout showed the familiar pattern: adoption doesn't spread evenly across the runway, it piles up against the deadline. Companies that wait find themselves competing for the same implementation partners, the same consultant hours, and the same internal IT capacity as everyone else who waited — at exactly the moment those resources are scarcest and most expensive. The single cheapest thing a company can do about e-invoicing is to start early.
The DIY trap: why building it yourself costs more than it saves
Faced with the mandate, a tempting thought arises in many IT departments: it's just XML — we can build this ourselves.
Berlin offered plenty of evidence for why that instinct is a trap. Not because generating a valid XRechnung or ZUGFeRD file is impossible — it isn't — but because "building e-invoicing" is not a project. It is a permanent commitment, and the standard itself proves the point.
The underlying European standard is being revised right now. EN 16931-1:2026 expands the semantic data model with 62 new elements — 52 new business terms and 7 new business groups — adding native support for cash discounts (Skonto), default interest, richer tax handling and exemption reasons, more line-level detail, and third-party charges. The 2017 standard it replaces will be withdrawn in March 2029.
And here is a first for the standard: until that withdrawal, two versions of EN 16931 — the 2017 and the 2026 edition — will coexist. Because the two are unlikely to be backwards compatible, every implementer effectively has to support every format twice: each EN 16931-conform XRechnung and ZUGFeRD profile once for EN 16931:2017 and once for EN 16931:2026. For anyone maintaining their own stack, the transition period doesn't just add work — it doubles it.
What that doubling looks like in practice is already visible in the format roadmaps:
- XRechnung 4.0 moves to the 2026 standard, while XRechnung 3.0 remains valid — and must be supported — until March 2029.
- Peppol BIS Billing v4 is in progress on the 2026 standard, with a release candidate expected around the end of 2026, while v3 stays in use alongside it.
- ZUGFeRD / Factur-X already anticipate some 2026 requirements, with a fully compliant update planned for spring 2027 — on top of the current profiles.
Whoever builds their own e-invoicing stack signs up to track, interpret, and implement every one of these changes — forever. That requires specialist regulatory knowledge, dedicated engineering capacity, and continuous testing against evolving validation rules. It is expertise most companies don't have, effort that produces zero competitive advantage, and cost that never ends.
A trusted service provider spreads exactly that effort across hundreds of customers. The economics are not close: what is a continuous, distracting burden in-house is a solved, always-current commodity when consumed as infrastructure. The build-vs-buy question in e-invoicing has a clear answer — and it gets clearer with every standards update.
E-invoicing is more than a format question — it's a process challenge
Here is the strategic reframing that Berlin crystallized, captured in one of the summit's better images: the mandate looks like a single point, but compliance in practice is a bed of nails — it touches many points at once.
Generating the correct XML is the part that gets the attention, and it is precisely the part that is already solved and outsourceable. What actually determines whether an e-invoicing project succeeds is the quieter work around it:
- Master data quality — supplier records, tax IDs, and routing information that were good enough for PDFs but fail structured validation.
- ERP integration — moving clean data in and out of systems that predate real-time structured exchange.
- Validation and release workflows — who reviews what, when, and how exceptions get resolved.
- GoBD-compliant archiving — a separate legal obligation that sits outside invoice generation entirely.
This is where the reframing pays off. If the compliance layer — formats, validation, transmission, staying current with the standards — is handed to a trusted provider, the mandate stops being a defensive cost and becomes something more interesting: a forced opportunity to modernize internal processes.
Companies that treat it this way come out ahead. Cleaning master data, automating invoice workflows, and connecting receiving and sending as one flow rather than two projects — these deliver measurable efficiency gains that outlast the compliance deadline. The mandate is the occasion; process automation is the prize. Companies that spend their scarce internal capacity rebuilding XML generators get neither.
It also explains why implementation partners and tax advisors featured in so many conversations in Berlin. The surrounding process design is where they add genuine value — and they add it best when they can build on a compliance foundation that simply works.
What comes after the invoice
Perhaps the clearest blind spot at the summit was what follows the mandate. The next phase is already taking shape: continuous transaction controls and digital VAT reporting, driven by the EU's ViDA ("VAT in the Digital Age") initiative. The direction across Europe is unmistakable — from documents to data, from periodic reporting to real-time.
An e-invoice is, at heart, structured data that tax authorities will increasingly want visibility into. A company that produces clean, well-governed structured data today is already positioned for the reporting obligations of tomorrow. A company that hacked together minimal format compliance will do this transition twice.
On transmission, the market signal in Berlin was consistent: PEPPOL is widely seen as the network of the future, and businesses continue to push for harmonization of international standards to simplify cross-border compliance. One more argument, incidentally, for infrastructure that evolves — rather than an integration that was finished once.
How fiskaly reads it
fiskaly's view is simple: format generation matters, but it should never be your problem. The infrastructure to produce and receive compliant German e-invoices — sending and receiving as one connected flow — exists today. fiskaly's E-INVOICE product is API-first and cloud-based by design, so when XRechnung, Peppol BIS, or the underlying EN 16931 model updates, customers don't re-integrate. The standard moves; the API stays.
Two principles follow:
- Compliance should be consumed, not built. For companies already working with fiskaly, adding e-invoicing means no new vendor, no new procurement cycle, no new compliance risk — it extends infrastructure already in place.
- Spend your energy where it compounds. The master-data, ERP, workflow, and archiving work — supported by implementation partners and advisors — is where internal investment creates lasting efficiency. A compliance provider's job is to be the reliable, standards-current foundation underneath it.
The technology is ready today. Being ready as a business is a process question — and every month of runway you use is a month you won't have to buy back later, at deadline prices.
Takeaways
- The market has to move now. Only 25–30% of B2B invoice volume is structured; receiving is already mandatory, issuing phases in from January 2027. Deadline-clustering makes waiting expensive.
- Don't build it yourself. Formats and standards change continuously — EN 16931-1:2026, XRechnung 4.0, Peppol BIS v4, ZUGFeRD 2027. In-house compliance is a permanent cost with no upside; a trusted provider is cheaper, faster, and always current.
- Think process, not format. The XML is solved and outsourceable. Master data, ERP integration, and workflow automation are where the mandate can be turned into lasting efficiency gains.
- Keep ViDA in view. Digital reporting is next. Clean structured data and evolving infrastructure today mean no second migration tomorrow.
fiskaly builds compliance infrastructure for fiscalization and e-invoicing across European markets. To talk about German e-invoicing specifically, get in touch with our team.
