Validate ZUGFeRD and XRechnung: Viewer, Validator, Checks

You check an e-invoice in three steps: view it, validate it technically, review the content. A viewer shows you the data, a validator tests format and business rules. The review for completeness and correctness stays with you, even when validation shows no errors.

Last updated: 29 October 2026

In short

View: A viewer makes the XML data readable, for example the tax administration's service at e-rechnung.elster.de.
Validate: A validator checks the format and the business rules; you can keep the report as evidence.
Review: You check tax rate, amounts and mandatory details yourself; validation does not replace that.

How do I see what is inside the e-invoice?

With a viewer. For a ZUGFeRD invoice you open the PDF, but the decisive data sits in the embedded XML file. If the structured part differs from the visual part, the data of the structured part applies (BMF: questions and answers on e-invoicing). An XRechnung is plain XML and needs a viewer. The tax administration offers a service to view an e-invoice at e-rechnung.elster.de; by its own words it is "ein unverbindlicher Service der Steuerverwaltung" (a non-binding service). A visualisation component of the KoSIT is also publicly available (xeinkauf.de).

What this means for you: Never open an XRechnung as text in an editor; use a viewer, and with ZUGFeRD look at the XML part, not only the PDF.

What does a validator check?

A validator checks the file against the technical rules. These cover the structure and mandatory fields as well as code lists and calculation rules. The KoSIT validation module is publicly available; its configuration combines the European standard EN 16931 with the XRechnung rules (xeinkauf.de). One business rule, for instance, is that the tax amount matches the stated tax rate arithmetically (BMF letter of 15 October 2025, para. 6b). XRechnung version 3.0 has been in force since 1 February 2024 (same source).

Check	What it shows	What it does not show
Viewer	The invoice data in readable form	whether the file is formally correct
Validator	Format errors and violated business rules	whether tax rate and amounts are right in substance
Your review	Completeness and correctness	technical errors in the XML

What this means for you: Viewer and validator complement each other; neither replaces your own review.

What does a clean validation give me?

The BMF sets clear limits for validation. A validation "ersetzt nicht die dem Empfänger obliegende Pflicht zur Überprüfung der Rechnung auf Vollständigkeit und Richtigkeit", meaning it does not replace the recipient's duty to check the invoice for completeness and correctness, but supports it. A business may rely on the technical result of a validation by a suitable validation application, as to format and business rules, if it observes the care of a prudent businessperson. For evidence it is advisable to keep the validation report (BMF letter of 15 October 2025, Rn. 35a). A content error can exist even when validation finds nothing; the BMF gives a wrong tax rate as an example (same letter).

What this means for you: Keep the validation report with the invoice, and still check the tax rate yourself.

Which formats count as an e-invoice at all?

An e-invoice is an invoice in a structured electronic format that allows electronic processing (§ 14 Abs. 1 Satz 3 UStG). According to the BMF, XRechnung and ZUGFeRD from version 2.0.1 meet this requirement, except the profiles MINIMUM and BASIC-WL (BMF letter of 15 October 2025). A plain PDF without structured data is not an e-invoice. If you check a ZUGFeRD file and the validator reports the profile MINIMUM or BASIC-WL, it is not permitted as an e-invoice.

What this means for you: If the validator shows an excluded profile, ask the issuer for a new file.

How long do I keep the checked e-invoice?

Eight years (§ 14b Abs. 1 UStG). You do not change the structured part after checking it. How you handle incoming invoices overall is in receive and read e-invoices.

What this means for you: File the original, not only a printout, and do not alter it.

How VAT GPT helps

Upload: Open "Expenses" and upload the ZUGFeRD PDF or XRechnung XML; the app reads the details on upload.
Check: You review the extracted amounts, tax rates and dates.
Send: The captured invoice then sits in your expenses. If you upload the same invoice again, VAT GPT shows the notice "Diese Rechnung ist bereits erfasst (gleiche Rechnungsnummer, gleiches Datum, gleicher Betrag)".

VAT GPT does not replace a validator or viewer. There are Free, Go (30 days free with all Pro features) and Pro. Try it for free

Frequently asked questions

How do I check a ZUGFeRD invoice? Open the embedded XML file in a viewer, have a validator test it and review amounts and tax rate yourself.

Where can I validate an XRechnung? The KoSIT validation module is publicly available (xeinkauf.de); the ELSTER service displays the invoice but is a viewer, not a seal of approval.

Is it enough if the validator shows no error? No; validation does not replace the check for completeness and correctness (BMF letter, Rn. 35a).

Do I have to keep the validation report? The BMF considers it advisable as evidence but does not require it (Rn. 35a). You must keep the invoice itself for eight years (§ 14b Abs. 1 UStG).