Data Model
Invoice Attachment (BG-24)
Definition
Business Group BG-24 (ADDITIONAL SUPPORTING DOCUMENTS) allows embedding or referencing attachments in an electronic invoice. Attachments can be embedded directly in the XML file as Base64-encoded binary data or referenced via a URI. Typical attachments include delivery notes, proof of service, or order confirmations. Maximum file size and permitted file types are implementation-dependent.
Switch to German:Rechnungsanhang (BG-24) (DE)
Related terms
Business Group (BG)A Business Group (BG) groups semantically related Business Terms (BT) of the EN 16931 standard into a logical unit. Examples include BG-4 (Seller), BG-7 (Buyer), or BG-23 (VAT breakdown). Business Groups can be nested and provide a structured organisation of the invoice data model.EN 16931EN 16931 is the European standard that defines the semantic data model of a core invoice. It specifies the mandatory and optional fields (Business Terms), their meaning, and the validation rules that apply to all conforming electronic invoices in the EU. Nationally implemented standards such as XRechnung, ZUGFeRD (EN 16931 profile), and Factur-X must comply with this standard.XRechnungXRechnung is the German standard for structured electronic invoices in public sector procurement (B2G). It is based on the European standard EN 16931 and is available in two syntaxes: UBL 2.1 and UN/CEFACT CII. Since 27 November 2020, federal public buyers have been required to accept electronic invoices in XRechnung format, and state and municipal authorities have been progressively included.ZUGFeRDZUGFeRD (Zentraler User Guide des Forums elektronische Rechnung Deutschland) is a hybrid invoice format that combines a human-readable PDF/A-3 file with embedded machine-readable XML data. The format is maintained by the Forum elektronische Rechnung Deutschland (FeRD) and exists in several profiles (MINIMUM, BASIC, EN 16931, EXTENDED). It is technically identical to the European Factur-X standard.