Important information: Please note that the federal invoice submission portals, ZRE and OZG-RE, will be consolidated by summer 2025. Following the consolidation, only the OZG-RE will be operated as the sole federal invoice submission portal. The operation of the ZRE will be discontinued as of 31 December 2025. Suppliers will receive all relevant information and the required details for future invoicing directly from the authorities to which they submit invoices. For further details, please refer to this article.
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 of the Federal Administration 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.
From 1 January 2025 – accompanied by transitional regulations – it will also be mandatory to use an electronic invoice (e-invoice) for transactions between domestic companies. The Federal Ministry of Finance is responsible for legal issues related to invoicing in the B2B sector. Companies do not need their own buyer reference for this purpose, as this is only used to address invoice recipients in the federal administration.
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).
Illustration: Structure of a buyer reference
Additional information on basic addressing in Germany’s federal states can be found in the document on Buyer Reference ID set-up (in German only) of the KoSIT.
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 of the Federal Administration only have one buyer reference or can they have multiple buyer references?
An invoice recipient in the federal administration has at least one buyer reference. Each authority or office may use several buyer references. They can request as many buyer references as they deem necessary. By specifying the appropriate buyer reference, authorities or offices with several buyer references ensure that the invoice is forwarded directly to the responsible budget manager. It is therefore essential that the buyer reference specified in the order is always used for invoicing. Please contact the invoice recipient directly if you have any questions about the buyer reference applicable to your contract. More information on the buyer reference is available on the KoSIT website. Federal authorities and offices are assigned their buyer reference (Leitweg-ID) by the Federal Government’s Central Finance Office (Zentrales Finanzwesen des Bundes, ZFB). Please contact erechnung@zrb.bund.de if you have any questions.
As an invoice recipient of the Federal Administration, where can I get a new/additional buyer reference?
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.
Please note that companies or invoice issuers do not generally need their own buyer reference, not even to implement the obligation to exchange invoices electronically between companies (B2B) that will apply from 1 January 2025. The Federal Ministry of Finance is responsible for legal questions regarding invoicing in the B2B area.
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 invoice submission portal does not accept the buyer reference, please contact your contracting authority to make sure they gave you the correct information. Please also check whether you have entered the buyer reference correctly. For example, the error message may be triggered by misplaced hyphens or extra spaces before or after the buyer reference.
If you didn’t make a mistake and can’t find a solution with the contracting authority, the contracting authority should forward the issue to the Federal Government’s Central Finance Office (Zentrales Finanzwesen des Bundes, 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. Please note that companies or invoice issuers do not generally need their own buyer reference, not even to implement the obligation to exchange invoices electronically between companies (B2B) that will apply from 1 January 2025. The Federal Ministry of Finance is responsible for legal questions regarding invoicing in the B2B sector.