Validation API Reference

The validation endpoint checks XML invoices against the EN 16931 standard and XRechnung-specific rules. It supports UBL 2.1, CII (Cross Industry Invoice), and ZUGFeRD profiles.

Endpoint

POST /v1/invoices/validate

Authentication

Pass your API key in the Authorization header:

Authorization: Bearer ps_live_...

Request

Send the raw XML invoice as the request body with Content-Type: application/xml.

curl -X POST https://api.postscale.io/v1/invoices/validate \
  -H "Authorization: Bearer ps_live_..." \
  -H "Content-Type: application/xml" \
  -d @invoice.xml

Query Parameters

Response

Success (200)

{
  "valid": true,
  "format": "xrechnung-ubl",
  "standard": "EN 16931",
  "profile_version": "3.0.2",
  "errors": [],
  "warnings": [
    {
      "rule": "BR-CL-01",
      "path": "/Invoice/InvoiceTypeCode",
      "message": "Invoice type code should use UNTDID 1001 subset",
      "severity": "warning"
    }
  ]
}

Validation Failed (200)

{
  "valid": false,
  "format": "xrechnung-ubl",
  "standard": "EN 16931",
  "errors": [
    {
      "rule": "BR-02",
      "path": "/Invoice/AccountingSupplierParty/Party/PartyName",
      "message": "An Invoice shall have a Seller name (BT-27)",
      "severity": "error"
    },
    {
      "rule": "BR-DE-01",
      "path": "/Invoice/AccountingSupplierParty/Party/Contact",
      "message": "A German invoice must contain seller contact information",
      "severity": "error"
    }
  ],
  "warnings": []
}

Error Codes

Validation Rules

The validator applies rules in three layers:

1. EN 16931 Business Rules (BR-*) — core European e-invoicing standard rules
2. XRechnung Rules (BR-DE-*) — Germany-specific rules (Leitweg-ID, contact info, payment terms)
3. Syntax Rules — UBL 2.1 or CII D16B schema validation

Each error includes the rule ID, the XML path where the violation occurred, and a human-readable message.

Rate Limits

Validation requests are rate-limited per API key: