On January 1, 2027, the grace period for e-bills ends for many companies. Anyone who makes more than 800,000 euros in turnover in 2026 may then no longer send invoices to other companies in Germany as PDF or on paper. The format question is quickly answered. Weeks costs something else: the question of how many systems a company actually writes invoices from and whether the data in them is suitable for a machine-readable invoice. This article classifies the duty and shows where conversions get stuck in practice.
Who from the 1. January 2027 is affected
Since the beginning of 2025, all companies in Germany must be able to receive e-bills. There were transitional periods when it was issued, and the first of these is now expiring. Until 31 December 2026, all companies are still allowed to write paper and PDF bills. After that, this only applies to companies whose total sales in the previous year 800,000 euros or less fraud. Decisive for the deadline is therefore the turnover of the current year 2026. Whoever lies above this must pay for domestic B2B sales from the 1. January 2027 issue structured e-bills.
One year later, from 2028, the obligation applies to everyone. Until the end of 2027, existing EDI procedures that do not comply with the European standard will also remain permitted. Excluded are permanent small-value invoices up to 250 euros gross, tickets, invoices from small business owners and invoices to private individuals.
In the case of mandatory receipt, according to the Federal Ministry of Finance, an e-mail inbox is sufficient. This sounds reassuring, but only helps conditionally. An XML file in the mailbox is received, but not yet read, checked and booked.
What counts as e-bill and what does not
An e-invoice within the meaning of the VAT Act is a structured data set that complies with the European standard EN 16931. A PDF is not an e-bill, not even if it comes from the ERP and is sent automatically. In Germany, two formats have become established: the XInvoice, a pure XML file, and ZUGFeRD, a PDF with embedded XML.
At ZUGFeRD it is worth a second look. The format is only allowed from version 2.0.1, and even then not in every profile. The profiles MINIMUM and BASIC-WL do not meet the VAT requirements, because they lack mandatory information. Anyone who already sends “ZUGFeRD bills” today should therefore check which profile the software actually generates.
The second BMF letter of 15 October 2025 also clarified that in hybrid formats the structured part leads. What is in the PDF is only a reading aid. All sales tax mandatory information must be in the XML, a reference to an attachment or a link is not enough. The XML is also the document that must be kept unchanged for eight years, not the PDF next to it.
The obligation sounds like an export format. In reality, it requires that every invoice is in a data field and not in a free text that a person has read so far.
Where the Conversion Actually Hangs
In a company that writes all the invoices from a current standard ERP, the transition is often an update and a few days of testing. This case is rarer in the middle class than you think. More often it looks like this: The invoices come from the ERP, the project accounting from an in-house development, maintenance contracts from an additional module, and credits or special cases builds someone in the accounting by hand in Word or Excel. Each of these sources must be able to generate e-bills from January.
The first task is therefore an inventory of all places where invoices are created. This sounds banal and regularly brings up surprises. Typical finds are a billing tool that a working student built years ago and is still running today, or a serial letter for annual license bills.
The second task is master data. On a PDF it does not matter whether the order number of the customer is in the subject, in a footer or not at all. Whoever reads the bill finds it or calls it. There is a field for this in the e-bill, and many large customers automatically reject invoices without a suitable reference. The same applies to VAT ID numbers, full addresses, performance periods and units. If this information is missing from the customer base or is in free text fields, even the best software cannot make a valid invoice from it. Cleaning up is hard work and needs the specialist department. However, it is not a lost work, because clean master data pays for each later Data Migration off again.
The third task is the special cases. Prepayment and final invoices, invoice corrections, credit procedures and invoices with proof of hours as an attachment work in the PDF workflow because a person interprets them. In structured format, each of these cases must be displayed cleanly. This also shows whether an in-house development can fulfill the obligation itself or needs an interface to a converter.
The entry page: Duty fulfilled, benefit given away
On the reception side, many companies have chosen the minimal solution in 2025: The mailbox accepts the file, a viewer makes it readable, is booked as before. That is permissible. But it gives away exactly the advantage that structured bills offer. When supplier, amount, tax rate and order reference arrive as data fields, an invoice can be automatically matched against order and goods receipt and pre-contracted without anyone typing.
This includes an examination at the entrance. BMF writing distinguishes between format errors, breaches of business rules and content errors. In the case of serious format errors, there is no formal e-invoice, with possible consequences for the VAT deduction. An automatic validation on receipt intercepts such cases before the invoice lands in the accounting, and the supplier can correct as long as this is still easy.
By the end of 2027, PDF invoices from smaller suppliers will also continue to arrive. A uniform input path is worthwhile for this mixed operation. Structured invoices are processed directly, PDFs are brought to the same data format via text recognition and AI-supported field extraction. Then the accounting works with one process instead of two.
What is realistic until January
Just under three months remain until the deadline, and December is largely over with annual accounts and public holidays. Those who have not yet started should keep the order strictly. In the first two weeks, the inventory of the invoice sources and a comparison with the ten highest-grossing customers are included: Which formats do they expect, which references do they require? Then the decision is made per source whether an update of the manufacturer is sufficient, whether a converter is connected or whether the in-house development has to be extended. The master data cleanup, which experience shows takes the longest, runs in parallel. In November, test calculations follow to real customers, with validation of each generated file against the norm. The retention of the XML files should also be clarified by then.
For in-house developments and older systems without manufacturer support, the schedule is tight, but feasible if the data plays along. An e-invoicing interface is technically not a major project. Libraries for XInvoice and ZUGFeRD are mature and the validation rules are public. It only becomes time-critical if it turns out that mandatory information is not maintained in the system at all. This is precisely why inventory belongs at the beginning and not at the end.
Conclusion
The e-invoicing obligation from 2027 is less a format change than a test of how well the own invoice data is structured. With a single current ERP, it is done in weeks. With several invoice sources, in-house developments and grown customer bases, she now needs attention. Those who use the changeover to automate the input side also turn a duty into an efficiency project. If you need to extend an existing application with e-bill or merge invoice data from several systems, we support you with individual software development. Talk to us.
Additional sources
- Federal Ministry of Finance – Questions and answers on e-bills
- Stuttgart Region – Mandatory e-invoices for domestic B2B sales
Note: This article reflects the status of 5 October 2026 and serves for general information. It does not replace tax advice. If and when your company is affected and how special cases are to be treated for VAT, please clarify with your tax advice.
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