Posting and document belong together
A posting says: EUR 1,190 were booked here. The document says: here is the invoice for it. Only the connection of the two makes the posting traceable — and traceability is a core requirement of the GoBD.
The voucher link is exactly this connection: from every posting a unique path leads to the corresponding original document.
Why this is trickier with e-invoices
With a paper invoice the document lay in the folder — physically findable. With an e-invoice the original is an XML file somewhere in the system. Without an explicit link, “somewhere” is not a good answer in an audit.
Precisely because the structured original is invisible and easy to misplace, the explicit connection is needed. Otherwise the document exists but is practically not assignable.
What a good voucher link delivers
It leads not to a view but to the original. It is unambiguous — one posting, one document, no mix-up. And it stays stable, even after months and across the export.
A link pointing to a re-generated PDF instead of the XML original misses the purpose. The evidence hangs on the original, not on the copy.
The voucher link in a tax audit
Auditors today ask specifically: show me the original document for this posting. Whoever then searches long or only presents a PDF weakens the orderliness — even if everything is correct in content.
With a clean voucher link the answer is one click. Precisely this effortlessness is what creates trust in an audit.
What you should watch
So the voucher link holds:
- Every posting refers uniquely to exactly one original document.
- The link points to the XML original, not to a generated view.
- The connection survives the export to the firm or DATEV.
- The original lies audit-proof, not in the changeable mailbox.
- The assignment stays stable over the whole retention period.