E-invoicing mandate: what the self-employed need to know now

Receiving and issuing are two separate obligations

Many small businesses start with receiving. You need a process for accepting, checking and archiving e-invoices. That can be an email inbox, a portal or another agreed transmission channel. What matters is that the original data is preserved, not just a printout.

Issuing depends on the specific transaction and recipient. B2B, B2G and consumer cases can be treated differently. Public-sector clients often require additional details such as a Leitweg-ID (routing ID required by public-sector recipients) or a purchase order reference. Software should not quietly invent these fields but ask for them visibly and check them before export.

What should small business owners prepare?

The Kleinunternehmerregelung (the German small business rule, § 19 UStG) does not mean every e-invoicing question automatically goes away. Even without showing VAT, correct identification, a description of the service, the amount and the appropriate note still matter. Whether a specific exception applies depends on the transaction and, if you are unsure, should be checked by a tax professional.

In practice, a fixed checklist helps: keep your company details up to date, keep client data complete, check payment terms and bank details, choose the right format and check the generated file with a suitable validator or through the recipient’s process.

• Keep company and client data complete
• Keep the small business (Kleinunternehmer) note accurate
• Document recipient requirements
• Archive the original file unchanged

Don’t mistake transition rules for a permanent exemption

Transition periods give businesses time to adapt their processes. They are not a license to ignore the requirements for good. The relevant cut-over dates can depend on turnover and on the recipient. Your process should therefore not rest on a single year but take into account the current legal situation and the specific job.

For Sumaro, this means: the application can prepare structured output and keep the workflow together. It does not replace a case-by-case tax review and does not claim any external certification. That limit belongs in credible product communication too.

Simple preparation in five steps

Start with the cases you actually invoice. Collect the requirements of your most important business and public-sector clients instead of covering every theoretical variant right away. Then test one complete flow from order to invoice to filing.

If a format is rejected, it has to be clear whether master data, references, tax details or the technical structure are missing. A logged review path saves follow-up questions later and makes the switch manageable for one person.

Practical example: an invoice to a business

Say you created a concept for an agency and are supposed to send the invoice as a structured file. First you check whether the agency requires a specific profile or transmission channel. Then you check the buyer details, a possible purchase order reference, the service period and the agreed payment term. Only when these details fit together do you generate a PDF, an XML or a hybrid file.

After the export, you open the human-readable view and also check the XML data with a suitable validator. If recipient, amounts and tax details match, you save the original file you sent and the proof of sending in the same record. That way you can explain later which version actually went to the client, without having to rely on a downloads folder.

• Confirm format and transmission channel in advance
• Compare the readable view with the structured data
• File the proof of sending next to the original file

Which data to check before the export

Most rejections aren’t caused by the file name, but by missing or contradictory data. So check sender and recipient, invoice number, date of service, line items, payment terms, bank details and reference fields as one connected checklist. Public-sector clients often add a Leitweg-ID (routing ID required by public-sector recipients); it should come from the client and not be filled in on a guess.

If your client rejects a file, don’t blindly change several fields at once. Note the exact error message, check the affected detail and then generate a new, traceable version. In small businesses especially, a documented correction path saves more time than an uncontrolled back-and-forth between PDF, email and portal.