This English version is provided for convenience. The German version is legally binding.
Template, not tax advice. Adapt this module to your actual processes and agree on it with your tax adviser (Steuerberater) before adding it to your process documentation.
1. Purpose and context
Under the German principles for the proper keeping and retention of books, records and documents in electronic form and for data access (GoBD – BMF circular of 28 November 2019, as amended in 2024/2025), every taxable business must document its data processing procedures in a comprehensible way, in particular in a process documentation (Verfahrensdokumentation, GoBD section 10).
This module describes the part of your invoicing process in which BelegBridge is used. It is intended to be added to your existing process documentation as a sub-section and does not replace it.
2. System description
BelegBridge is a transient conversion and validation gateway for electronic invoices under EN 16931 (XRechnung and ZUGFeRD/Factur-X). It is not an archiving system and does not store invoice contents.
- Web application: receives files, detects format and profile, and renders results and previews.
- KoSIT validator with the official XRechnung configuration: checks the XML against the schema and the business rules of EN 16931 and XRechnung.
- Mustang/veraPDF: checks hybrid invoices (ZUGFeRD/Factur-X) for PDF/A-3 conformance and the embedded XML.
All components run in the same infrastructure in Germany or the EU. The validation services operate in an isolated network without internet access. Invoice contents are processed exclusively in volatile memory.
3. Process 1: free validator (available today)
- Upload: The user uploads an XML or PDF file (up to 15 MB) via the website or the API.
- Format detection: BelegBridge identifies the syntax (CII or UBL) and the profile and rejects unsafe XML constructs.
- Official validation: The file is checked with the KoSIT validator and, for PDF files, additionally with Mustang/veraPDF.
- Report: The user receives the result with translated notes and, on request, a readable preview. The user can keep the result (for example as a PDF preview or printout) in their own records.
- No storage: The file contents are discarded immediately after the response. The authoritative original remains the invoice file received or sent by the user.
4. Process 2: paid bridge In preparation / early access
The following process describes the planned paid bridge. It only applies once the service is available and has been booked.
- Receipt: Invoice data arrive from the connected sources (Stripe or PayPal webhook, email or API).
- Enrichment: BelegBridge adds the mandatory seller details exclusively from the stored seller profile (name, address, VAT ID or tax number, contact person, bank details).
- Generation: An EN 16931 XML and a ZUGFeRD 2.3 PDF/A-3 file are generated in volatile memory; amounts and taxes are calculated to the cent.
- Validation & dispatch: Every generated file is validated with the KoSIT validator and Mustang before dispatch. Only files without errors are sent to the invoice recipient and to the DATEV mailbox or accounting system you specify. Files with errors are not sent; you are notified instead.
5. Responsibilities
| Task | Responsible |
|---|---|
| Correct content of the invoice (§ 14 UStG) | Invoice issuer (your company) |
| Maintenance of seller master data (bridge) | Your company |
| Technical validation against official rule sets | BelegBridge |
| Generation and dispatch (bridge, planned) | BelegBridge, according to your configuration |
| Archiving: unalterable, machine-readable, for the statutory retention period (currently eight years for invoices) | Your company, in its archiving system (for example DATEV or a document management system) |
| Process documentation and internal control system | Your company |
6. Internal control system
- Every file is checked against the official KoSIT rules (and, for PDFs, Mustang/veraPDF); with the bridge, files with errors are not dispatched.
- Amounts and taxes are calculated to the cent; inconsistencies are reported as errors.
- Mandatory seller details come exclusively from the stored seller profile and cannot be overridden by incoming data.
- Recommended internal controls: regular spot checks of dispatched invoices, reconciliation with payment receipts, and keeping the validation result together with the invoice.
- Access to the customer account only for authorized persons in your company.
7. Change documentation
The rule sets used are versioned. BelegBridge currently validates against XRechnung 3.0.2 with the corresponding KoSIT validator configuration. Changes to rule sets (for example a new XRechnung version) are documented with their effective date. Please record in your process documentation from which date you used which version, so that results remain reproducible.
8. Template text for your process documentation
You can copy the following text and adapt the placeholders in square brackets:
Validation and generation of electronic invoices with BelegBridge
1. Scope: [Company] has been using BelegBridge since [date] for the technical validation of incoming and outgoing electronic invoices (XRechnung, ZUGFeRD) [and – once available – for the automatic generation of outgoing invoices from [Stripe/PayPal/email]].
2. Procedure: Files are checked with the official KoSIT validator (XRechnung configuration) and, for PDF files, with Mustang/veraPDF. The result is reviewed by [name/role]; invoices with errors are corrected before being sent or are returned to the sender.
3. No storage: BelegBridge does not store invoice contents. The authoritative original is the invoice file sent to the recipient or received from the sender.
4. Archiving: Invoice files are stored unchanged in the format in which they were received or sent in [archiving system, e.g. DATEV or document management system], unalterable and machine-readable, for the statutory retention period (currently eight years). Responsible: [name/role].
5. Controls: [Spot checks, reconciliation with payment receipts, filing of the validation result with the invoice.]
6. Versions: Rule sets used: XRechnung [3.0.2], KoSIT configuration [version]. Changes are documented with their date.
Last updated: [date] · Approved by: [name]
9. Note
This module is a template and does not constitute tax or legal advice. It describes BelegBridge in its current state; the bridge (process 2) is in preparation. Please agree on the final wording with your tax adviser (Steuerberater). The legal requirements for your invoices, archiving and process documentation remain with your company.
Last updated: November 2026