UBL 2.1 Validator

Generic UBL validator. Accepts any UBL 2.1 document (Invoice, CreditNote, Order, DespatchAdvice…). Envelope checks only.

How it works

UBL (Universal Business Language) is an OASIS standard defining around 60 B2B document types under a consistent XML schema family. This validator only runs envelope checks — the structure common to all types — without diving into per-document business rules (EN 16931 invoices, OpenPEPPOL orders, etc.). Pipeline:

1. XML parsing (DOMParser in browser, fast-xml-parser fallback).
2. Type detection from root element name + default namespace.
3. Envelope rules application (below).

Supported UBL documents

The validator auto-recognises:

• Billing: Invoice, CreditNote, DebitNote.
• Order: Order, OrderResponse, OrderResponseSimple, OrderChange, OrderCancellation.
• Logistics: DespatchAdvice, ReceiptAdvice.
• Catalogue: Catalogue, CatalogueRequest.
• Payment: RemittanceAdvice, Statement, Reminder.
• Response: ApplicationResponse.

Rules checked

• Root + namespace: the root element must belong to the UBL 2.1 list above and its default namespace must start with urn:oasis:names:specification:ubl:schema:xsd:.
• cbc:UBLVersionID (optional): if present, value in { 2.0, 2.1, 2.2, 2.3, 2.4 }.
• cbc:ID: document identifier, mandatory, non-empty.
• cbc:IssueDate: mandatory issue date in ISO 8601 format YYYY-MM-DD.
• cbc:DocumentCurrencyCode: mandatory for monetary documents (Invoice, CreditNote, DebitNote, Statement, Reminder, RemittanceAdvice), ISO 4217 three-letter code.
• Mandatory parties: each type has its own required cac: elements. Invoice/CreditNote/DebitNote ⇒ cac:AccountingSupplierParty + cac:AccountingCustomerParty. Order ⇒ cac:BuyerCustomerParty + cac:SellerSupplierParty. DespatchAdvice ⇒ cac:DespatchSupplierParty + cac:DeliveryCustomerParty, etc.

Relation to PEPPOL / EN 16931

This validator is generic: it only checks conformance to the UBL 2.1 OASIS layer. To validate an invoice against the European EN 16931 norm or the PEPPOL BIS Billing 3.0 rules (BR-*, BR-CO-*, BR-S/Z/E/AE/G/IC/O-*, LegalMonetaryTotal totals, EAS code list, etc.), use instead:

• EN 16931 Validator for the European norm.
• PEPPOL Validator for BIS Billing 3.0.

The UBL validator is useful for non-invoicing documents (Order, DespatchAdvice, Catalogue) or for a quick envelope check before pushing an Invoice into a stricter pipeline.

Limits

• No full XSD validation — only the envelope rules above.
• No calculation rules (totals, VAT).
• No partner rules (OpenPEPPOL, XRechnung, Factur-X CIUS).
• No XAdES signature verification (a signed Invoice is accepted as-is).

Privacy

Related documentation

• UBL / PEPPOL — overview of the standard and its adoption.
• OASIS UBL 2.1 specification — the official reference.
• PEPPOL BIS specifications — PEPPOL profiles for invoicing, ordering, catalogue.