General information
What is a buyer reference?
In order for the invoice issuer or sender to be able to send an electronic invoice to the correct address, the invoice recipient must be uniquely identified and addressable. The buyer reference is called “Leitweg-ID” in German.
The buyer reference enables electronic addressing and forwarding of the e-invoice by the Federal Central Invoice Submission Portals of the federal government to the connected ERP or release systems of the authorities of the federal administration.
The buyer reference is specified in the standard XRechnung invoice in the field ‘Buyer reference’ (BT-10) and must be transmitted as mandatory information on every e-invoice.
How is a buyer reference structured?
The buyer reference is basically made up of three components:
- Basic address,
- Specific address and
- Check digit.
The basic address is used to distinguish whether the invoice recipient belongs to the federal administration or to a federal state:
- 991: The invoice recipient is part of the direct federal administration or a constitutional body and receives electronic invoices via the ZRE.
- 992: The invoice recipient is part of the direct federal administration and receives electronic invoices via the OZG-RE.
- 993: The invoice recipient is part of the direct federal administration and receives electronic invoices via its own solution (neither ZRE nor OZG-RE).

Set-up of a Buyer Reference ID
Additional information on buyer references in Germany’s federal states can be found in the current state synopsis of the KoSIT (document with current implementation status of the states, in German only).
When should a buyer reference be used and when not?
The buyer reference must be indicated on every electronic invoice to public contracting authorities of the federal administration.
When placing the order, the public contracting authority provides the invoice issuer (contractor) with the buyer reference. The ZRE and OZG-RE platforms also have a list of connected buyer references within the web entry. However, please only use the listed identification number when you are placing the order for an associated electronic invoice.
Allocation of buyer references
Does each invoice recipient only have one buyer reference?
An invoice recipient in the federal administration has at least one buyer reference.
The configuration of the buyer reference in an authority is based on the structure of internal invoice processing. Authorities with several buyer references ensure that the invoice is addressed directly to the area responsible for handling of the invoice by specifying the corresponding buyer references. It is therefore essential that the buyer reference specified in the order is always used for invoicing.
Where can I get a new/additional buyer reference as the invoice recipient?
The allocation of buyer references is regulated at federal and state level:
- The Central Federal Finance Office (ZFB) is responsible for federal authorities and contracting authorities connected at federal level. Further information on applying for the buyer reference can be requested from the ZFB via our contact form.
- The issuing bodies for state authorities can be found in the current state synopsis of the KoSIT (document with current implementation status of the states, in German only).
As a federal invoice recipient, how can I change my buyer reference?
If you want to change your existing buyer reference, you can reach the responsible contact person by email via our contact form.
Generally, it is possible to adjust the buyer reference structure, but it requires adjustments to documents in procurement and purchasing for invoice issuers and should thus be well thought out.
Support
What does the ZRE/OZG-RE error message 'buyer reference is not valid' mean?
If the buyer reference provided by the contracting authority is not accepted by the invoice receipt platform, first contact your contracting authority directly.
If you cannot find a joint solution to the problem, the client should address the problem with the ZFB.
Whom can invoice recipients contact if they have problems with the buyer reference?
If you have any questions or problems with the buyer reference at federal level, you can reach the responsible contact person by email via our contact form.