Electronic invoices to federal, state and local authorities: e-invoice portals, regulations and special features at a glance
Electronic invoicing, or e-invoicing for short, is no longer a topic for the future. However, what will be gradually introduced in Germany from January 1, 2025 for the electronic exchange of invoices between companies has already been a digital reality in another area for some time. This refers to the electronic invoicing of public clients at federal, state and municipal level as well as public companies. This is because what has often taken place “under the radar” of the general public to date has already been the case for digital invoice exchange in B2G for several years.
Here, e-invoicing is not only a reality, but already a legal obligation for most companies that work with public clients. Whether as a supplier, service provider or construction company: Anyone who wants to issue invoices to the public administration or public companies in Germany must know and fulfill the specific requirements of eInvoicing in each federal state. And this is where the problem lies: because of the federal structures in Germany, e-invoicing to the administration is not standardized. Quite the opposite: not only the invoice formats and portals, but also the obligations and requirements in the 16 federal states are regulated differently.
Finding your way through the German “e-invoicing jungle” to the administration not only saves time and nerves. Maintaining an overview is crucial for many invoice issuers in order to avoid delays in payments or even penalties. We have therefore summarized the most important regulations of the individual federal states and the federal government for you and show you what you need to know as an invoicing party from the private sector - in a practical and to-the-point manner.
Electronic invoices to federal authorities
After all, invoicing to the federal administration is regulated in a standardized manner. Electronic invoicing to federal authorities has been mandatory for invoices issued to direct federal authorities since November 27, 2020. The basis for this is the E-Invoicing Ordinance (ERechV), which is based on EU directives and ensures uniform standards in the federal administration.
For companies, this means that every invoice submitted to the federal government must comply with the requirements of the regulation, particularly with regard to format and transmission.
Who are the federal government's invoice recipients?
Direct recipients of federal invoices include ministries, federal authorities and other organizations that are directly subordinate to the federal administration. Examples include the Federal Office of Administration, the Federal Police and the Federal Foreign Office. The same requirements apply to indirect federal authorities such as the Federal Printing Office or public foundations, although a different portal is used for invoicing.
The two central portals for electronic invoicing
Two central platforms are available to make the e-invoicing process standardized and efficient:
Central invoice receipt portal (ZRE)
The ZRE is the main portal for invoices to direct federal authorities. It is designed to check and securely forward invoices in accordance with the requirements of the ERechV.
- Internet address: zre.bund.de
- Intended use: The portal offers companies the option of submitting invoices via web upload, e-mail or PEPPOL.
- Group of affiliated invoice recipients: All direct federal authorities.
OZG-RE (Online Access Act-compliant invoice receipt platform)
The OZG-RE is available for indirect federal authorities, such as the Federal Printing Office or public institutions.
- Internet address: xrechnung-bdr.de
- Intended use: Similar to the ZRE, submissions are made via web upload, e-mail or PEPPOL.
- Group of affiliated invoice recipients: All indirect federal authorities
- ZRE (central invoice receipt portal): For invoices to direct federal authorities such as ministries or the Federal Office of Administration.
- OZG-RE (online access law-compliant invoice receipt platform): For indirect federal authorities such as the Federal Printing Office or foundations under public law.
Format requirements for electronic B2G invoices and mandatory information
The only accepted format for invoices to the federal government is the XRechnung. It is machine-readable and enables automated processing in the authorities' IT systems. In addition to the usual invoice data such as invoice amount, service description and tax number, some specific mandatory details are particularly important. This includes the routing ID, a unique identifier that identifies the invoice recipient within the federal administration. Without this ID, the invoice cannot be processed correctly. If available, an order number must also be provided, as this is crucial for internal allocation. The invoice issuer's bank details and precise information on the terms of payment, such as discount periods or payment targets, are also mandatory.
Invoices can be submitted in several ways: Companies can upload their invoices directly to the respective portals via web upload, transfer them via PEPPOL or, in exceptional cases, send them as an XML file by email. The size of the invoice and embedded attachments must not exceed 15 MB. For larger documents, such as extensive reports or technical documentation, the option of external referencing is available. In this case, the attachments are saved outside the invoice and referenced via a link. Such attachments may be up to 200 MB in size.
E-invoicing to federal states, municipalities and other public organizations
Here is a more detailed description of each federal state. The aim is not only to present the regulations factually, but also to integrate practical tips and advice for companies:
Baden-Württemberg was one of the first federal states to consistently implement electronic invoicing. Since January 1, 2022, invoices over €1,000 to public administrations must be submitted electronically.
Submissions are made via the ZRE-BW portal (zhttps://www.zre-bw.de/re-bw.de), which was specially developed for the needs of the state authorities. Invoices can be submitted as XRechnung or in ZUGFeRD format from version 2.0. Particularly practical: the portal supports both upload via a web interface and transmission via PEPPOL or email.
What should companies bear in mind?
- Routing ID: This is mandatory as it serves as the central address for the correct allocation of the invoice. Companies should ensure that they receive the routing ID from the client in good time.
- Attachment size: The maximum size of the invoice including attachments is 15 MB and no more than 100 documents may be attached.
For companies that regularly work with state authorities, the use of a PEPPOL access point is recommended, as this improves the automation and security of the transmission.
Bavaria takes a different approach to e-invoicing. There is no central obligation for companies to issue electronic invoices. Instead, it is up to the contracting authorities to accept e-invoices. Since April 18, 2020, all authorities and institutions in Bavaria have been obliged to accept e-invoices if they are offered by invoice issuers.
As no central portal is provided, submissions are made by email, web form or web upload, depending on the authority. The XRechnung and ZUGFeRD formats are accepted.
What should companies bear in mind?
- Regional differences: In Bavaria, many municipalities and cities work with their own regulations. Example: The city of Munich has specific requirements, including a maximum file size of 5 MB.
- Coordination: As Bavaria is organized on a decentralized basis, companies should clarify in advance with the respective invoice recipient which transmission channels and formats are preferred.
For companies that work with several Bavarian authorities, a flexible software solution that supports different formats and transmission channels is recommended.
The capital city introduced electronic invoicing early on and sets clear standards. Since December 31, 2022, e-invoicing has been mandatory for all public administrations and institutions. Invoices of € 1,000 or more must be submitted electronically via the OZG-RE portal (xrechnung-bdr.de).
Special requirements:
- Format: Only the XRechnung format is accepted. Other EN 16931-compliant formats are only permitted in consultation with the authorities.
- Attachment size: Directly embedded attachments may not exceed 15 MB. Larger files (up to 200 MB) can be referenced externally.
For companies that regularly work with Berlin authorities, we recommend integrating a software solution that automatically creates XRechnung invoices and takes the routing ID into account.
The state of Brandenburg introduced the obligation to issue invoices electronically on April 1, 2023. This applies to all invoices to state authorities from an amount of € 1,000. As in Berlin, invoices are submitted via the OZG-RE portal.
Special features:
- Routing ID: Invoices cannot be processed without this unique identifier. Companies should clarify at an early stage whether the routing ID is correctly integrated into the invoicing system.
- Flexibility: In addition to web upload, Brandenburg also supports transmission via PEPPOL.
Companies that have no previous experience with XRechnung should allow for a transition period to train and test the processes internally.
Bremen has been using mandatory electronic invoicing for invoices of €1,000 or more since November 27, 2020. The central portal zERIKA (e-rechnung.bremen.de) offers a user-friendly platform for this.
Advantages for companies:
- Both XRechnung and ZUGFeRD 2.0 are accepted.
- Submission is possible in several ways: web browser, web upload, e-mail or PEPPOL.
Important notes:
- Attachments may not exceed a maximum size of 20 MB.
- The use of PEPPOL is recommended, as this speeds up processing.
Small and medium-sized companies in particular benefit from the flexibility of the portal.
In Hamburg, companies have had to submit all invoices to public administrations electronically since January 1, 2022. The central Hamburg e-invoicing portal (https://www.hamburg.de/service) is available for this purpose.
Important details:
- Format: In principle, only the XRechnung format is accepted. Companies that are not subject to the obligation can also submit invoices in PDF format or as ZUGFeRD - but only by email and by arrangement.
- Transmission channels: In addition to direct upload in the portal, PEPPOL and e-mail are also supported.
- Route ID: This is essential for addressing.
Companies that frequently work with Hamburg authorities should consider using PEPPOL, as this shortens the processing time.
In Hessen, the e-invoicing obligation for invoices over €1,000 comes into force on April 18, 2024. There is no central invoice receipt portal; invoices can be sent by email or via PEPPOL, depending on the authority.
Notes:
- Format: XRechnung and ZUGFeRD 2.0 are accepted.
- Attachment size: Attachments may not exceed 22 MB in size. When using e-mail, only one invoice should be sent per message.
For companies that operate at both state and municipal level, it is advisable to integrate a flexible system that supports both transmission channels.
In Mecklenburg-Vorpommern, the obligation to issue invoices electronically was introduced on April 1, 2023. The federal state relies on the central OZG-RE portal (xrechnung-bdr.de).
Special requirements:
- Format: Only XRechnung is legally accepted. Other formats, such as ZUGFeRD, are not permitted.
- Attachment size: Directly embedded attachments may be a maximum of 15 MB in size; larger attachments can be referenced externally (up to 200 MB).
- Transmission methods: Invoices can be submitted via web upload, e-mail or PEPPOL.
For companies that do not have an internal solution for creating XRechnung, the use of a service provider is recommended.
There is currently no general obligation to issue invoices electronically in Niedersachsen. However, all authorities are obliged to accept electronic invoices. The central portal NAVO (rechnung.niedersachsen.de) is used for this purpose.
What needs to be considered?
- Format: XRechnung and ZUGFeRD are accepted.
- Attachment size: Invoices including attachments may not exceed 40 MB.
The use of the NAVO portal offers an easy introduction to electronic invoicing, especially for smaller companies.
Nordrhein-Westfalen provides the central portal eRechnung NRW (erechnung.nrw). Although there is no general obligation, all authorities at state level are obliged to accept electronic invoices.
Details for companies:
- Format: XRechnung and ZUGFeRD are accepted.
- Attachment size: Maximum 15 MB and up to 200 attachments per invoice.
- Transmission methods: Invoices can be submitted in electronic format by e-mail, PEPPOL or web upload.
Companies should clarify at an early stage whether their business partners at municipal level also use the central portal or prefer other channels.
In Rhineland-Palatinate, mandatory e-invoicing will be introduced on April 1, 2025. The central portal for submission is the ZRE-RP (e-rechnung.service.rlp.de).
Special requirements:
- Format: XRechnung and ZUGFeRD are accepted.
- Size limit: Invoices and attachments may not exceed 20 MB.
For companies that have long-term contracts with state authorities, it makes sense to implement the XRechnung functionality before 2025 in order to be prepared in good time.
Saarland uses the same portal as Rhineland-Palatinate, the ZRE-RP (e-rechnung.service.rlp.de). The obligation to use e-invoicing has been in effect since January 1, 2022.
Notes:
- The same requirements as Rhineland-Palatinate.
- Companies can submit their invoices in electronic format via web upload, email, or PEPPOL.
For companies operating across borders, using PEPPOL is recommended as a secure and efficient transmission method.
There is no general obligation to issue invoices electronically in Saxony. The central portal is the OZG-RE (xrechnung-bdr.de).
Requirements:
- Format: XRechnung is mandatory. Other formats such as ZUGFeRD can be accepted in exceptional cases.
- Size limit: attachments up to 15 MB directly; larger ones up to 200 MB externally.
The use of a PEPPOL access point is recommended for companies with high invoice volumes.
With the Saxony-Anhalt service portal (serviceportal.sachsen-anhalt.de), Saxony-Anhalt offers a central platform for electronic invoicing. However, there is no general obligation to use e-invoicing.
Details:
- Format: XRechnung and ZUGFeRD are accepted.
- Size limit: Maximum 20 MB incl. attachments.
The option of submitting invoices directly via a user-friendly web form is particularly practical.
There is also no general obligation to eInvoice in Schleswig-Holstein. The Schleswig-Holstein service portal (serviceportal.schleswig-holstein.de) is the central point of contact for submission.
Important notes:
- Format: XRechnung and ZUGFeRD are accepted.
- Size limit: Maximum 20 MB.
For companies with low invoice volumes, the portal is a good way to gain initial experience with eInvoicing.
In Thuringia, there is no general obligation to use eInvoicing. The central portal is also the OZG-RE (xrechnung-bdr.de).
Requirements:
- Format: XRechnung is the standard.
- Size limit: attachments up to 15 MB directly; larger ones up to 200 MB externally.
Companies should check the requirements of the respective invoice recipient before submission.
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