Supporting documents for invoices to DB
For Deutsche Bahn, you must embed supporting documents such as timesheets, proofs of performance or photos directly in the XML of the XRechnung. The email to Deutsche Bahn may contain only a single file: the XRechnung. Up to 200 embedded attachments in the formats PDF, CSV, PNG and JPEG are permitted.
You can find all of Deutsche Bahn's other requirements regarding mandatory fields and sending in the article XRechnung to Deutsche Bahn: requirements.
What are supporting documents?
Supporting documents prove that the invoiced service was actually provided. Typical examples are timesheets, measurement records, delivery notes, acceptance reports or photos of the goods. Deutsche Bahn requires them in many cases, depending on the order and the service. If they are missing, the responsible department cannot check the invoice. It is therefore best to clarify when the order is placed which proofs your contact person expects.
Deutsche Bahn's rules for attachments
According to DB's information sheet on XRechnung (as of 13.02.2024), the following applies:
- All attachments are embedded in the XML of the XRechnung, not attached to the email as separate files.
- Exactly one file is permitted per email: the XRechnung as XML.
- A maximum of 200 attachments per XRechnung.
- Permitted formats: PDF, CSV, PNG and JPEG.
- Links to files and additional XML files are not permitted.
- The embedded files must not themselves contain further attachments, for example no PDF with attached files.
An email containing an XRechnung plus an additional timesheet as a PDF does not meet these requirements. The same applies to an invoice that is also sent by post or as a PDF.
How embedding works technically
For attachments, XRechnung provides the group "Additional supporting documents" (BG-24). Each attachment receives an identifier (BT-122) and can carry a description (BT-123). The file itself is stored Base64-encoded in field BT-125, together with the file name and file type.
Base64 increases the size of every file by roughly a third. A 3 MB PDF therefore becomes about 4 MB in the XML. With many photos or scanned proofs, the XRechnung quickly becomes large. This has two consequences:
- Reduce file sizes before embedding: compress photos, save scans at a lower resolution, combine several pages into one PDF.
- Check the limits of your own mail server: many mail servers limit the size of outgoing emails. If the XRechnung exceeds this limit, it will not even arrive.
Also keep an eye on your "Sent Items" folder. Anyone who sends many large invoices fills up their own mailbox faster than expected.
Difference from the federal portals
Different rules apply to invoices sent to federal authorities via the OZG-RE. There, in addition to embedded attachments of up to 15 MB, so-called large attachments of up to 200 MB in total are possible, which are referenced via a link in BT-124. Further file types, such as XLSX, are also permitted. At Deutsche Bahn, by contrast, links are not allowed. You can read more about the federal portals in the article ZRE and OZG-RE: sending XRechnung to the federal government.
Embedding attachments with faktoora
In faktoora, you select files such as proofs of performance or photos while creating the invoice. They are embedded directly in the e-invoice, not sent as a loose attachment, just as large recipients like Deutsche Bahn require. Find out more on the page Create e-invoices.
Frequently asked questions
May I attach the timesheet to the email as a second file?
No. DB allows exactly one file per email: the XRechnung. The timesheet must be embedded in the XML.
Which file formats does Deutsche Bahn accept as attachments?
PDF, CSV, PNG and JPEG. Links to external files and additional XML files are not permitted.
How many attachments may an XRechnung to DB contain?
A maximum of 200 embedded attachments per XRechnung.
Do the rules also apply when sending via Peppol?
DB's requirements for embedding concern the XRechnung itself and therefore apply regardless of the transmission channel. Via Peppol, too, you submit attachments embedded in the XML.