# CII Standard

CII is the UN/CEFACT XML syntax used by EN 16931 and by ZUGFeRD and Factur-X profiles.

## What is CII?

CII (Cross Industry Invoice) is an XML-based e-invoicing standard from UN/CEFACT. UN/CEFACT publishes CII in versioned directories. The European EN 16931 syntax binding uses CII D16B, while a target profile package can select a later CII release. Always use the schemas and rules for the recipient profile.

> **Foundation for ZUGFeRD and Factur-X**: ZUGFeRD and Factur-X use CII as their embedded XML syntax. The selected profile and recipient rules determine whether a file is accepted.

## Key Features

- EN 16931 syntax binding uses CII D16B
- A profile package can select another CII directory
- Structured XML syntax
- Embedded syntax for ZUGFeRD and Factur-X
- Target profiles restrict elements and code lists
- Validation against matching schemas and rules

## Advantages of CII Format

### UN/CEFACT publication
Published by UN/CEFACT; acceptance depends on the target profile

### Cross-Industry
Designed for multiple sectors; target profiles can restrict the data

### Versioned
UN/CEFACT publishes maintained releases

### Integration
ERP or middleware can map the XML; profile rules still apply

## ZUGFeRD and Factur-X Hybrid Profiles

| Level | Requirements | Fields | Complexity |
| --- | --- | --- | --- |
| MINIMUM | Accounting data only | Selected header and totals | Low |
| BASIC WL | Header data without line items | Header and totals | Medium |
| BASIC | EN 16931 subset with line items | Header, lines, and totals | Medium |
| EN16931 | EN 16931 data model | EN 16931 fields | High |
| EXTENDED | Additional fields beyond EN 16931 | Additional profile fields | Very high |

## Invoice Type Codes (UNTDID 1001)

### Commercial invoice (380)
Standard B2B invoice — the default in EN 16931. Usage: Default for most B2B transactions

### Credit note (381)
Cancels or reduces a previously issued invoice. Usage: Refunds, returns, corrections downward

### Debit note (383)
Adds charges to a previously issued invoice. Usage: Additional charges, corrections upward

### Corrected invoice (384)
Replaces an earlier invoice with corrected values. Usage: Full replacement of an earlier invoice

### Prepayment invoice (386)
Issued before delivery to request advance payment. Usage: Advance payments and deposits

### Self-billed invoice (389)
Buyer-issued invoice on the seller's behalf (Gutschrift in German). Usage: Self-billing arrangements

## Technical Specifications

| Aspect | Specification | Details |
| --- | --- | --- |
| EN 16931 Syntax Binding | CEN/TS 16931-3-3 | UN/CEFACT CII D16B |
| Character Encoding | UTF-8 | Unicode support for international characters |
| Namespace | urn:un:unece:uncefact:data:standard | Unique XML namespace identification |
| Document Type | 380 (Commercial Invoice) | UN/EDIFACT-compliant document classification |

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

## Resources & Links

- [UN/CEFACT Portal](https://unece.org/trade/uncefact)
- [UN/CEFACT XML Schemas](https://unece.org/trade/uncefact/xml_schemas)
- [ZUGFeRD Format](/resources/compliance/zugferd-format)
- [UBL Universal Business Language](/resources/compliance/ubl-universal-business-language)
- [DIN EN 16931-1 Standard](/resources/compliance/din-en-16931-1-standard)