How to Send E-Invoices in Germany: Channels, Deadlines, Pitfalls

To send e-invoices in Germany, most businesses attach the file to an email: an XRechnung as XML, or a ZUGFeRD PDF with embedded XML. German VAT law prescribes the format, not the channel. Issuing e-invoices becomes mandatory from 1 January 2027 for domestic suppliers above EUR 800,000 turnover, and for all from 2028. Federal authorities accept invoices only through the OZG-RE portal.

This guide is for finance and ERP teams setting up outgoing e-invoicing for German customers, including foreign suppliers. It compares the four channels, explains when the obligation starts and what the federal portal requires, and ends with a pre-send check.

Who has to send e-invoices in Germany?

The obligation follows from Section 14 of the German VAT Act (§ 14 UStG). Under § 14 Abs. 2 Satz 2 Nr. 1 UStG (opens in a new tab), an invoice for a supply to another business must be an e-invoice if both the supplier and the customer are established in Germany. Three groups follow from that:

An e-invoice is defined by its format. According to § 14 Abs. 1 Satz 3 UStG it is an invoice "issued, transmitted and received in a structured electronic format" that allows electronic processing. In practice that means XRechnung, or ZUGFeRD from version 2.0.1 except the MINIMUM and BASIC WL profiles. The structure behind XRechnung is explained in What is XRechnung?.

When does sending e-invoices become mandatory?

Receiving has been mandatory for German businesses since 1 January 2025. For issuing, § 27 Abs. 38 UStG (opens in a new tab) sets transition periods based on when the supply takes place:

The threshold uses total turnover (Gesamtumsatz) under § 19 UStG for the previous year, so 2026 decides for 2027. Worked examples are in Germany e-invoicing 2027. Small businesses under the small-business rule (Kleinunternehmerregelung, § 19 UStG) and small-amount invoices up to EUR 250 gross are exempt from issuing.

Between domestic businesses you may already send e-invoices without asking. § 14 Abs. 1 Satz 5 UStG requires the recipient's consent only where no e-invoicing obligation exists, for example toward consumers.

Which channels can you use to send an e-invoice?

German law names no channel for B2B. Four routes are common:

For EDI, § 27 Abs. 38 Nr. 3 UStG allows formats that do not meet EN 16931 for 2027 supplies until 31 December 2027, with the recipient's consent. From 2028, an agreed EDI format remains valid only if the invoice data can be extracted correctly and completely into an EN 16931 format (§ 14 Abs. 1 Satz 6 Nr. 2 UStG).

On the receiving side, an email inbox is enough according to the German Federal Ministry of Finance (BMF letter of 15 October 2024, para. 40). Every German business customer can therefore accept your file by email. What the recipient does with it is covered in How to receive e-invoices in Germany.

How do you send e-invoices to German federal authorities?

The federal e-invoicing ordinance (E-Rechnungsverordnung, ERechV) prescribes the route. Under § 4 Abs. 3 ERechV (opens in a new tab), suppliers must use a federal administration portal and register a user account first. Since September 2025 that portal is the OZG-RE alone; the former ZRE was merged into it (federal e-invoicing news (opens in a new tab)). This applies to foreign suppliers too.

After registering and activating a channel, you have four options:

1. Web entry (Weberfassung): type the invoice directly in the portal. Suited to a few invoices without your own e-invoicing software.
2. Upload: upload an XRechnung created elsewhere.
3. Email: send the file to an address the OZG-RE generates for your account. It stays the same and is shown on the portal's start page.
4. Peppol: your software sends through a Peppol service provider or your own access point. The federal site describes this as the only channel for machine-to-machine and bulk sending.

The platform checks each invoice automatically for formal errors and rejects faulty files with a notification. An invoice that cannot be matched to a user account is rejected without notice (§ 4 Abs. 3 and 4 ERechV). § 5 ERechV (opens in a new tab) also requires the Leitweg-ID (buyer reference, BT-10), bank details, payment terms and your email address. Whether private customers need a Leitweg-ID is answered in Leitweg-ID for companies.

German states and municipalities implement Directive 2014/55/EU under their own rules. Some run their own portals, others connect to the OZG-RE. The contracting authority tells you which inbox to use, usually together with the Leitweg-ID.

OZG-RE rules for attachments, file size and email text

The OZG-RE enforces strict rules on what arrives with the invoice. Many corporate supplier portals work in a similar way:

Sources: the federal e-invoicing FAQ (opens in a new tab) and the page on the OZG-RE email channel (opens in a new tab). How to embed a PDF with Base64 is shown in XRechnung attachments.

There is no legal rule for the file name of an XRechnung. A descriptive name such as RE-2026-0042_Muster-GmbH.xml still helps the recipient. For ZUGFeRD 2.1 and later, the embedded XML is named factur-x.xml for the MINIMUM to EXTENDED profiles and xrechnung.xml for the XRECHNUNG profile.

Step by step: send an e-invoice

1. Collect recipient data. Ask for the invoice address, the preferred format and references: the Leitweg-ID for authorities, the purchase order number (BT-13) and buyer reference (BT-10) for companies.
2. Create the invoice. Generate one XRechnung or ZUGFeRD file per invoice in your invoicing system.
3. Validate the file. Check the XML against the KoSIT rules. Target: no finding at level "error".
4. Check the content. Service, date of supply, VAT rate and totals. A technical check cannot see a wrong quantity.
5. Send. One invoice per email, no loose extra attachments; for authorities, use the activated OZG-RE channel. Record the date sent.
6. Track the status. The OZG-RE can notify you of status changes. For B2B, ask key customers for a receipt confirmation.
7. Archive the original. Keep the file you sent unchanged for eight years (§ 14b UStG (opens in a new tab)).

Common mistakes when sending e-invoices

When an invoice comes back rejected, look up the rule in the list of XRechnung validation errors and follow How to fix XRechnung validation errors.

How to prepare and check the file with docutools.pro

1. If you have no invoicing system yet, open the XRechnung generator. In the "Company" step enter invoice number, date, seller and buyer, and for authorities the "Buyer reference / Leitweg-ID". Single invoices are free and need no account.
2. Under "Generate & download", choose "XRechnung XML" for authorities or "ZUGFeRD PDF" for business customers. The result is a file you can attach directly. CSV batch creation for many invoices is part of the Pro plan (Pro).
3. If you received a Leitweg-ID, run it through the Leitweg-ID validator. It runs in your browser and checks structure and check digit, not whether the ID is registered.
4. Upload the XML to the XRechnung viewer. The file is sent to our server for checking. The "KoSIT validation" checks the way the KoSIT validator does (configuration 2026-08-31) and shows "KoSIT-conformant / Valid XRechnung" or "Not KoSIT-conformant".
5. Compare the "Extracted data" table with your invoice. The viewer does not display the Leitweg-ID, IBAN or addresses, so check those fields in your invoicing system.

The free tier includes 2 uploads per day of up to 500 KB per file. Unlimited checks are part of the Pro plan; see pricing. A full creation walkthrough is in How to create an XRechnung.

Checks after your first invoices go out

• Did a test invoice reach your most important customer, and could they read it?
• If you supply federal authorities: is your OZG-RE account registered and the channel activated?
• Do you know the Leitweg-ID and the correct inbox for every public customer?
• Is every sent file stored unchanged in your archive?

Browse more guides on XRechnung for portals, fields and versions.

Sources

• § 14 UStG: issuing invoices (German VAT Act) (opens in a new tab)
• § 27 UStG: transition rules (para. 38) (opens in a new tab)
• § 4 ERechV: data model and transmission (opens in a new tab)
• § 5 ERechV: content of the electronic invoice (opens in a new tab)
• E-Rechnung des Bundes: FAQ (opens in a new tab)
• E-Rechnung des Bundes: OZG-RE email channel (opens in a new tab)
• E-Rechnung des Bundes: news on the ZRE and OZG-RE consolidation (opens in a new tab)

Last reviewed: October 2026

This article is general information, not tax or legal advice.