Free Validation API

E-Invoice Validator

Validate invoices against EN 16931 and format-specific rules. POST /v1/validate is free, no API key required, no credits consumed.

API Documentation Try It Below

Validate an Invoice

Drop a PDF, XML, or JSON file to validate it against EN 16931 rules.

Drag and drop your invoice file here

PDF, XML, or JSON up to 10 MB

API Example

Send invoice JSON to validate it before generating a PDF.

POST /v1/validate Free, no key needed

$ curl https://api.thelawin.dev/v1/validate \
  -H "Content-Type: application/json" \
  -d '{"format":"zugferd","invoice":{"number":"RE-2025-001","date":"2025-01-17","seller":{"name":"Muster GmbH","country":"DE","vat_id":"DE123456789"},"buyer":{"name":"Kunde AG","country":"DE"},"items":[{"description":"Beratung","quantity":8,"unit_price":150}]}}'

Response (200 OK)

{
  "valid": true,
  "format": "zugferd",
  "errors": [],
  "warnings": []
}

Supported Formats

Validates all major EU e-invoice standards against their specification rules.

ZUGFeRD 2.4

PDF/A-3 + CII XML. German B2B standard.

Factur-X 1.0.8

PDF/A-3 + CII XML. French standard, Chorus Pro compatible.

XRechnung 3.0.2

UBL XML. German B2G, KoSIT-validated.

UBL 2.1

OASIS standard. Widely used across the EU.

CII D16B

UN/CEFACT Cross Industry Invoice.

Peppol BIS 3.0

UBL-based. EU, UK, AU, SG, NZ, UAE.

FatturaPA 1.2.2

Italian SDI format. Codice Destinatario support.

Format-Specific Validators

Dedicated pages with format-specific validation rules and examples.

XRechnung Validator

Validate XRechnung 3.0.2 against KoSIT Schematron rules.

ZUGFeRD Validator

Validate ZUGFeRD 2.4 PDF/A-3 and embedded CII XML.

Factur-X Validator

Validate Factur-X 1.0.8 for Chorus Pro compatibility.

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