# UBL (Universal Business Language): 2.1, Peppol, XRechnung

UBL is an OASIS XML standard for invoices, orders, credit notes, and other structured business documents.

## What is UBL?

UBL (Universal Business Language) is an OASIS XML standard. It defines schemas for invoices, credit notes, orders, and despatch advice. A profile such as Peppol BIS selects a UBL version and adds business rules.

> **Peppol Standard**: Peppol BIS Billing 3.0 uses the UBL 2.1 Invoice and CreditNote syntaxes. Other UBL versions or profiles are not interchangeable without validation.

> **One model, two syntaxes, many rule sets**
>
> The EN 16931 family: EN 16931-1 is the semantic model with business terms (BT) and business groups (BG). Two syntax bindings carry it: UBL 2.1 (CEN/TS 16931-3-2) and UN/CEFACT CII D16B (CEN/TS 16931-3-3). Peppol BIS Billing 3.0, NLCIUS and OIOUBL are CIUS used with UBL; XRechnung, the German CIUS, exists in UBL and CII. ZUGFeRD and Factur-X are hybrid PDF/A-3 files with embedded CII XML. They are not a CIUS but define profiles (MINIMUM, BASIC WL, BASIC, EN 16931, EXTENDED, XRECHNUNG); MINIMUM and BASIC WL do not cover EN 16931.

## Key Features

- OASIS-standardized XML schemas
- Versioned document structures
- Invoice and CreditNote syntaxes
- Order and DespatchAdvice syntaxes
- Code lists selected by the target profile
- Validation against profile rules

## Advantages of UBL

### OASIS Standard
International recognition and governance by OASIS

### Modularity
Reusable components and flexible structure

### Peppol Compatibility
Base syntax for Peppol BIS Billing 3.0; profile rules still apply

### Document types
Schemas for procurement, invoicing, and transport processes

## UBL Document Types

### Invoice (UBL 2.1/2.3)
Standard invoice for goods delivery and services Application: Main document for e-invoicing

### Credit Note (UBL 2.1/2.3)
Credit notes and invoice corrections Application: Cancellations and refunds

### Order (UBL 2.1/2.3)
Electronic orders Application: Procurement and e-commerce

### Despatch Advice (UBL 2.1/2.3)
Shipping notifications Application: Logistics and supply chains

### Receipt Advice (UBL 2.1/2.3)
Receipt confirmations Application: Goods receipt processes

## UBL Versions

### UBL 2.4 (2024-06-20) (Current)
Improvements: Two new document types and schema updates

### UBL 2.3 (2021) (Previous)
Improvements: Ten new transport-related document types

### UBL 2.2 (2018) (Previous)
Improvements: Additional procurement, transport, directory, and agreement documents

### UBL 2.1 (2013) (Previous)
Improvements: Syntax version used by Peppol BIS Billing 3.0

### UBL 2.0 (2006) (Previous)
Improvements: Earlier UBL 2.x release; use the version required by the target profile

## UBL Implementation

1. Download and integrate UBL 2.x schemas
2. Perform business process mapping
3. Implement code lists
4. Set up validation engine
5. Apply the selected Peppol BIS rules and validate the file
6. Execute test scenarios

## Technical Specifications

### Schema Language (XML Schema Definition (XSD))
W3C-compliant schema definition

### Namespace (urn:oasis:names:specification:ubl:schema:xsd)
Unique OASIS namespace identification

### Code Lists (ISO, UN/ECE, OASIS)
Standardized value lists for consistency

### Data Types (ISO 15000-5 (ebXML CCTS))
Core Component Technical Specification

## UBL Schema Info

| Current Version | Documents | OASIS Status |
| --- | --- | --- |
| UBL 2.4 | 70+ | Approved |

- [Convert invoice](/en/pdf-to-ubl?source=resource)
- [Validate XML](/en/xrechnung-validator?source=resource)
- [Developer API](/en/developer-api?source=resource)

## Resources & Links

- [UBL 2.4 Schemas](https://docs.oasis-open.org/ubl/)
- [OASIS UBL TC](https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ubl)
- [Peppol Network](/resources/compliance/peppol-network-guide)
- [CII Format](/resources/compliance/cii-cross-industry-invoice)
- [DIN EN 16931-1](/resources/compliance/din-en-16931-1-standard)
- [XRechnung Standard](/resources/compliance/xrechnung-standard)