# Peppol Validator

> Free online tool for validating Peppol BIS Billing 3.0 and EN 16931 XML invoices. No signup, no API key, no rate limits.

## When to use

Use Peppol Validator when you need to:
- Validate a Peppol UBL 2.1 or CII XML invoice before sending it via the Peppol network
- Check if an invoice complies with EN16931 business rules or Peppol BIS Billing 3.0 constraints
- Debug validation errors from a Peppol Access Point rejection
- Convert an XML invoice to a human-readable PDF

How to use: POST the XML to https://peppolvalidator.com/api/v1/validate and check the `status` field in the JSON response ("valid", "invalid", or "error"). No authentication required.

Do not use for: non-XML files, PDF invoices (extract XML first), or non-Peppol/non-EN16931 formats.

## What it does

Peppol Validator checks UBL 2.1 and CII (Factur-X / ZUGFeRD) XML invoices and credit notes against:
- EN 16931 (CEN) business rules (BR-*)
- Peppol BIS Billing 3.0 rules (PEPPOL-EN16931-*)
- Country-specific schematron rules

The format is detected automatically from the XML namespace. Results include the exact rule ID, severity (error or warning), XPath location, and a plain-language explanation.

## API

Endpoint: POST https://peppolvalidator.com/api/v1/validate
Content-Type: application/xml (raw XML body) or multipart/form-data (file upload)

Response: JSON with status ("valid", "invalid", or "error"), list of errors and warnings, invoice metadata (format, specification, seller country, invoice number).

No authentication required. Free for all usage.

## Supported formats

- UBL 2.1 XML invoices (Peppol BIS Billing 3.0)
- UBL 2.1 XML credit notes
- CII XML invoices (EN 16931 / Factur-X / ZUGFeRD)

## MCP Server

MCP endpoint: https://peppolvalidator.com/mcp (Streamable HTTP transport)
Tools: validate_invoice, xml_to_pdf, get_verification_challenge, submit_feedback
Discovery: https://peppolvalidator.com/.well-known/mcp

## Agent Feedback

Agents can report validation outcomes and accuracy issues via HATCHA-verified feedback.
1. Call get_verification_challenge (or POST /api/feedback/hatcha) to get a challenge token
2. Solve the challenge (SHA-256, arithmetic, or base64)
3. Call submit_feedback (or POST /api/feedback/agent) with the token, answer, and feedback data
Fields: agentId, toolUsed (validate_invoice/xml_to_pdf), outcome (success/failure/error), comment, accuracyIssue, ruleIds, invoiceFormat, apiIssues

## Key pages

- https://peppolvalidator.com/ - Validator tool (drag and drop XML files)
- https://peppolvalidator.com/developers - API documentation
- https://peppolvalidator.com/ai-agents - AI agent integration guide and skill
- https://peppolvalidator.com/peppol-validation-errors - Reference of 311+ validation rules with fix guides
- https://peppolvalidator.com/factur-x-validator - Factur-X / CII validator
- https://peppolvalidator.com/ubl-validator - UBL 2.1 validator
- https://peppolvalidator.com/peppol-credit-note-validation - Credit note validation guide
- https://peppolvalidator.com/xml-to-pdf - XML to PDF converter
- https://peppolvalidator.com/en16931-business-terms - EN 16931 business term reference

## Country guides

- https://peppolvalidator.com/peppol-belgium - Belgium (B2B mandate live since Jan 2026)
- https://peppolvalidator.com/peppol-france - France (B2B mandate phased from Sep 2026)
- https://peppolvalidator.com/peppol-germany - Germany (receiving mandatory since Jan 2025)
- https://peppolvalidator.com/peppol-spain - Spain (Crea y Crece Law, B2B mandate pending)
- https://peppolvalidator.com/peppol-netherlands - Netherlands (B2G mandatory, high B2B adoption)
- https://peppolvalidator.com/peppol-united-kingdom - United Kingdom (NHS mandate, HMRC consultation)
- https://peppolvalidator.com/peppol-italy - Italy (SDI e-invoicing since 2019)
- https://peppolvalidator.com/peppol-norway - Norway (Peppol pioneer, B2G mandatory)
- https://peppolvalidator.com/peppol-australia - Australia (Peppol adoption growing)

## Educational content

- https://peppolvalidator.com/what-is-peppol-e-invoicing - How Peppol works
- https://peppolvalidator.com/peppol-network - Four-corner model, AS4, SML/SMP
- https://peppolvalidator.com/peppol-mandates - Mandates by country
- https://peppolvalidator.com/peppol-access-points - Access Point providers
- https://peppolvalidator.com/blog - Articles on Peppol, UBL, CII, and e-invoicing

## Section-specific llms.txt files

- https://peppolvalidator.com/api/llms.txt - API endpoint reference
- https://peppolvalidator.com/developers/llms.txt - Full developer documentation
- https://peppolvalidator.com/blog/llms.txt - Blog article index

## For more detail

See https://peppolvalidator.com/llms-full.txt for API response schema, validation rule categories, and complete page inventory.