e-Invoicing in OTM: Supported formats and document types

 

OTM generates electronic invoices as a ZUGFeRD/Factur-X hybrid format using the XRechnung 3 profile, fully compliant with the European standard EN 16931. Each invoice is created as a PDF/A-3 file with an embedded XML dataset. This gives your customers an invoice they can read and print like a normal PDF, while also allowing the data to be imported into accounting systems – without any manual retyping.

Supported document types

OTM maps the following document types as e-invoices:

Code	Document type	Description
AR	Customer invoice	Standard final invoice to the customer. Includes all line items of the job.
TR	Partial invoice	Progress/partial invoice for jobs that are not yet fully completed.
DGU	Credit note (customer)	Invoice correction / credit note to the customer. References the original invoice.
GU	Resource credit note	Credit note for freelancers or resources (Self-Billed Invoice). The company creates the document on behalf of the service provider.
RR	Resource invoice	Invoice created by the resource itself. The resource enters its own invoice number, and OTM generates the resulting e-invoice document.

For billing freelancers and resources, OTM supports two variants: resource credit notes as Self-Billed Invoices, where the company issues the document on behalf of the service provider, and resource invoices, which are created by the resource itself in OTM after entering its own invoice number. Both document types are generated as ZUGFeRD e-invoices.

Tax scenarios

When generating e-invoices, OTM automatically applies the relevant tax scenario:

• Domestic supplies/services with the standard VAT rate or a reduced VAT rate
• Intra-Community supplies and services (EU)
• Reverse-charge mechanism (shift of VAT liability)
• VAT-exempt exports to third countries
• Small business scheme pursuant to § 19 UStG

Payment details

Each e-invoice contains your company’s complete payment details, including IBAN and BIC for SEPA transfers as well as the payment terms. These details are transmitted in structured form within the XML section, so the recipient can import them directly for payment processing.

Leitweg-ID: mandatory information for public-sector customers

The Leitweg-ID is a unique identifier used by public contracting authorities in Germany to identify recipients and route electronic invoices. If you issue invoices to government agencies, public institutions, or other public-sector entities, providing the Leitweg-ID is generally mandatory.

Structure of the Leitweg-ID

The Leitweg-ID consists of up to 46 characters and follows a fixed pattern:

[Main routing]–[Fine routing]–[Check digit]

Example: 04011000-12345-67
04011000 = main routing (e.g., a federal ministry)
12345 = fine routing (department/unit)
67 = check digit

The main routing identifies the authority or institution, while the fine routing identifies the specific unit or department within the organization. The check digit is used for technical validation.

Leitweg-ID in OTM

In OTM, the Leitweg-ID is stored per customer master record. In addition, for each customer you can maintain an alternative billing address with its own Leitweg-ID – for example, if the invoice recipient is a different authority or department than the commissioning unit.

As soon as a Leitweg-ID is stored for a customer, OTM automatically uses it as the electronic address in the e-invoice XML (according to ICD-0204). For customers without a Leitweg-ID, the email address is used as the electronic address instead. No manual switching is required.

Buyer Reference

In addition to the Leitweg-ID, OTM also supports transmitting a Buyer Reference per customer. This field is included in the e-invoice as an additional buyer reference and can be used by the recipient for internal allocation – e.g., purchase order numbers, file references, or cost centers. If no Buyer Reference is stored, OTM automatically uses the customer company code.

e-Invoicing: ZUGFeRD, Factur-X and XRechnung

Benefits, differences, and what businesses need to keep in mind

What is an e-invoice?

An e-invoice is not simply a PDF file sent via email. A genuine electronic invoice contains structured, machine-readable data in XML format, built according to the European standard EN 16931. This allows invoice data to be imported into accounting systems automatically – without manual entry.

In Germany, three formats are particularly relevant:

The three formats at a glance

Comparison: ZUGFeRD / Factur-X vs. XRechnung

Feature	ZUGFeRD / Factur-X	XRechnung
Data format	PDF/A-3 + embedded XML	Pure XML
Human-readable (without special software)	Yes (PDF view)	No (XML viewer or visualization required)
Machine-readable	Yes (XML component)	Yes (entirely)
EN 16931 compliant	Yes (from version 2.0)	Yes
Mandatory for public-sector contracts	Accepted in some cases	Yes (required)
B2B invoices	Yes	Yes
International use	EU-wide (Factur-X)	Mainly Germany
Profiles / level of detail	Minimum, Basic WL, Basic, EN 16931 (Comfort), Extended	One profile (standard)

Benefits of electronic invoice formats

Why switching to e-invoicing pays off
Automated processing	Invoice data is imported directly into your accounting – without manual retyping. This reduces errors and saves significant time.
Cost savings	No printing, postage, or paper costs. Studies show savings potential of 60–80% compared to paper invoices.
Faster payments	Electronic invoices are delivered and processed faster. This shortens cycle times and improves liquidity.
Legal compliance	You meet the requirements of the Wachstumschancengesetz (Growth Opportunities Act), the GoBD and EU Directive 2014/55/EU.
Audit-proof archiving	E-invoices in PDF/A format can be archived long-term and meet the requirements for GoBD-compliant retention.
Fewer process breaks	The entire invoicing process – from creation to sending to archiving – runs digitally and end-to-end.
Sustainability	No paper, no physical shipping – an active contribution to environmental protection.
Future-proofing	E-invoicing is becoming the EU-wide standard. Switching now prepares you for upcoming regulations (e.g., the EU-wide reporting system “ViDA”).

Key advantage of ZUGFeRD / Factur-X: the hybrid format

The biggest practical advantage of ZUGFeRD is its hybrid approach: the invoice is both a normal PDF (which you can print, read, and archive) and a machine-readable XML file (which can be processed automatically).

In concrete terms:

• Recipients without specialized software can open, read, and print the invoice as usual as a PDF.
• Recipients with accounting software can automatically import and process the embedded XML data.
• One file for everyone – you don’t need different formats for different customers.

ZUGFeRD profiles: choosing the right level of detail

ZUGFeRD offers different profiles that vary in the scope of the transmitted data:

Profile	Description	EN 16931
Minimum	Minimal dataset – comparable to the information on an accounting voucher	No
Basic WL	Extended accounting voucher with additional contact details	No
Basic	Structured invoice data incl. line items	No
EN 16931 (Comfort)	Full compliance with the EU standard – recommended profile	Yes
Extended	Extended with industry-specific additional information	Yes (superset)

What do you need to consider?

1. Legal deadlines in Germany

The Wachstumschancengesetz (Growth Opportunities Act) regulates the phased introduction of mandatory e-invoicing in B2B:

2. Technical requirements

• Software support: Your invoicing software or ERP system must be able to create and read e-invoices in ZUGFeRD or XRechnung format. Check with your vendor whether an update is required.
• PDF viewer: To read ZUGFeRD invoices, any PDF reader is sufficient. The XML data is processed in the background.
• Validation: Use validation tools to ensure your e-invoices meet the technical requirements of EN 16931.

3. Mandatory information on e-invoices

E-invoices must contain the same mandatory information as traditional invoices pursuant to § 14 UStG:

• Full name and address of the issuer and the recipient
• Tax number or VAT ID of the issuer
• Invoice date and a sequential invoice number
• Quantity and type of supplied goods or scope of services
• Net amount, VAT rate, VAT amount, and gross amount
• Date of supply or service
• Leitweg-ID (only for invoices to public-sector customers in XRechnung format)

4. Archiving

• E-invoices must be retained in their original format (a printout alone is not sufficient).
• The retention period is 10 years (pursuant to § 14b UStG and § 147 AO).
• Storage must be GoBD-compliant: immutable, complete, traceable, and timely.

5. Which format for which purpose?

Use case	Recommended format
Invoices to public-sector customers (federal level)	XRechnung (required)
Invoices to municipalities and states	XRechnung (depending on state law)
Domestic B2B invoices	ZUGFeRD (EN 16931 or Extended profile)
International B2B invoices (EU)	Factur-X / ZUGFeRD
Mixed recipients (with/without software)	ZUGFeRD (hybrid format)

Special considerations for language service providers

The same obligations apply to translation agencies, language service providers, and freelancers. The following points are particularly relevant:

• International customers: If you invoice customers in France or other EU countries, Factur-X/ZUGFeRD offers the best compatibility.
• Public-sector contracts: If you translate for public authorities, you will typically need XRechnung with a Leitweg-ID.
• Different customers, one format: ZUGFeRD is ideal because the hybrid format works for both tech-savvy enterprise customers and smaller clients without specialized software.
• Accounting software: Check whether your current solution supports e-invoicing. Many vendors have already provided updates or offer add-ons.

Summary

• ZUGFeRD / Factur-X is the most flexible solution: one format for all recipients, readable with or without specialized software, compatible across the EU.
• XRechnung is mandatory for invoices to public contracting authorities in Germany.
• Since January 2025, all companies must be able to receive e-invoices; by 2028, all companies must also be able to send them.
• Make sure you choose the right profile (at least EN 16931), include the correct mandatory details, and ensure GoBD-compliant archiving.
• Switching saves costs, speeds up payments, and makes your business future-proof.

If you have questions about e-invoicing or OTM, please contact our Customer Service.