ZUGFeRD Validator
Validate invoice data against ZUGFeRD 2.4 and EN 16931 before generating PDFs. Catch errors early with a single API call.
What Gets Validated
The /v1/validate endpoint checks your invoice JSON against
ZUGFeRD 2.4 requirements before PDF generation.
PDF/A-3 Compliance
Ensures the invoice data will produce a valid PDF/A-3 document with correctly embedded XML attachment.
CII XML Structure
Validates that all fields map correctly to UN/CEFACT Cross-Industry Invoice XML elements required by ZUGFeRD.
EN 16931 Conformance
Checks business rules defined by the European e-invoicing standard: VAT calculations, line item totals, date logic, and payment terms.
Required Fields
Verifies all mandatory fields are present: invoice number, date, seller/buyer details, VAT IDs, line items, and currency codes.
Validate via API
Same payload as /v1/generate, validated without producing a PDF.
curl -X POST https://api.thelawin.dev/v1/validate \
-H "Content-Type: application/json" \
-d '{
"format": "zugferd",
"invoice": {
"number": "RE-2026-001",
"date": "2026-01-15",
"currency": "EUR",
"seller": {
"name": "Muster GmbH",
"country": "DE",
"vat_id": "DE123456789"
},
"buyer": {
"name": "Tech Corp",
"country": "DE"
},
"items": [{
"name": "Consulting",
"quantity": 8,
"unit": "HUR",
"unit_price": 150.00,
"vat_rate": 19
}]
}
}'
Free Validation
/v1/validate does not consume your monthly generation quota.
Validate as often as needed during development. Typical response time is 20-50ms.