Validate XRechnung Invoice using REST-API

Validate an XRechnung XML invoice against the full German B2G compliance stack. The API checks CII or UBL XML schema conformance, EN 16931 Schematron business rules, and the additional XRechnung CIUS constraints defined by KoSIT — ensuring your invoices are accepted by German government portals such as ZRE and OZG-RE.

POST https://api.invoicexml.com/v1/validate/xrechnung

Code Example

curl -X POST https://api.invoicexml.com/v1/validate/xrechnung \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "[email protected]" \
  -F "version=2.3.2" \
  -F "profile=extended"

Try it out online — no coding required

Upload an invoice and get a full compliance report instantly, right in your browser.

Try It Online

Request

Parameter	Type	Description
file *	binary	The invoice file to validate. Accepted format: standalone XRechnung XML document (CII or UBL syntax).
version	string	Standard version (e.g. `2.3.2`). Defaults to the latest supported version.
profile	string	Compliance profile. Values: `minimum`, `basicwl`, `basic`, `en16931`, `extended`. Defaults to `en16931`.

Content-Type: multipart/form-data

Headers

Header	Value
Authorization *	Bearer YOUR_API_KEY
Content-Type	multipart/form-data

Response

200 The invoice is valid. Returns a JSON object confirming compliance.

Content-Type: application/json

{
  "valid": true,
  "detail": "Your invoice is xrechnung compliant and meets the EN 16931 specifications.",
  "data": {
    "schemaValid": true,
    "schematronValid": true,
    "conformanceLevel": "EN16931"
  }
}

200 The invoice has validation errors. Returns a JSON object with structured error information.

{
  "valid": false,
  "detail": "Validation failed with 3 error(s)",
  "data": {
    "conformanceLevel": "EN16931"
  },
  "errors": {
    "xml": [
      "[BR-01] An invoice shall have a specification identifier.",
      "[BR-06] An invoice shall contain the seller name.",
      "[BR-08] An invoice shall contain the document total amount."
    ],
    "friendly": [
      {
        "rule": "BR-01",
        "line": null,
        "message": "The invoice is missing a specification identifier (BT-24)."
      },
      {
        "rule": "BR-06",
        "line": null,
        "message": "The seller must have a name (BT-27). Add the seller's name."
      },
      {
        "rule": "BR-08",
        "line": 2,
        "message": "Line item 2: The document total amount with VAT is missing or incorrect."
      }
    ]
  }
}

Error Reference

When an invoice fails validation, the errors.xml array contains one entry per violated business rule. Each entry starts with the rule identifier (e.g. [BR-01]) followed by the raw Schematron description.

The errors.friendly array provides a parallel set of user-facing messages — one object per violation. Each object contains:

Field	Type	Description
rule	string	The business rule identifier (e.g. `BR-01`, `BR-DE-15`).
line	int \| null	The 1-based invoice line item number the error relates to, or `null` when the error applies to the document level.
message	string	A plain-language explanation of the violation, suitable for displaying directly to end users.

Status	Meaning	Action
200	Validation completed. Check `valid` to determine compliance.	If `valid` is `false`, inspect `errors.xml` or `errors.friendly`.
401	Missing or invalid API key.	Check the `Authorization` header.
422	File is not a valid PDF or XML document.	Ensure you are uploading a supported file format.

Frequently Asked Questions

What is XRechnung validation?

XRechnung validation checks your XML invoice against the German CIUS (Core Invoice Usage Specification) of EN 16931. It applies all EN 16931 core business rules plus the additional XRechnung-specific constraints defined by KoSIT, such as mandatory Leitweg-ID and stricter field requirements.

What is the difference between XRechnung and ZUGFeRD validation?

XRechnung validation expects a standalone XML file and applies stricter German CIUS rules. ZUGFeRD validation expects a hybrid PDF with embedded XML and applies ZUGFeRD profile rules. Both share the EN 16931 core rules, but XRechnung adds B2G-specific constraints.

Does this endpoint accept PDF files?

No. The XRechnung validator expects a standalone XML document (CII or UBL syntax). If you have a ZUGFeRD or Factur-X PDF, use the /v1/validate/zugferd or /v1/validate/facturx endpoints instead.

Which XRechnung versions are supported?

The validator supports XRechnung 2.0, 2.1, and 3.0. The version is auto-detected from the CustomizationID in the XML. Validation rules are aligned with the current KoSIT validator release.

Is the Leitweg-ID mandatory?

Yes. XRechnung requires a Leitweg-ID (routing identifier) in the BuyerReference field for B2G invoicing. The validator flags its absence as a rule violation.