E-Invoice Glossary
The complete reference for European e-invoicing terminology. From EN16931 business terms to country-specific identifiers.
Popular Terms
BT-1 Invoice Number
BT-1 is the unique sequential identifier assigned to an invoice by the seller, required in every EN 16931 e-invoice.
BT-10 Buyer Reference
BT-10 is a text field in the EN 16931 semantic model where the buyer's reference identifier — such as a purchase order number, project code, or routing ID — is carried on the invoice. Optional in EN 16931, but mandatory in key CIUS profiles like XRechnung and Peppol BIS 3.0.
BT-24 Specification Identifier
BT-24 is the mandatory EN 16931 field that declares which specification — the base standard, a CIUS (like XRechnung or Peppol BIS), or an extension — an invoice claims to conform to. Validators use it to choose which rule set to apply, so an incorrect value leads to the wrong validation or outright rejection.
Chorus Pro
Chorus Pro is France's government platform for receiving and processing B2G e-invoices, mandatory for all invoices to French public entities.
Codice SDI
The Codice SDI (Codice Destinatario) is a 7-character alphanumeric code that routes FatturaPA invoices to the correct recipient through Italy's SDI system.
CTC (Continuous Transaction Controls)
Continuous Transaction Controls (CTC) are tax-compliance regimes in which transaction data is submitted to, or cleared by, the tax authority at or near the moment an invoice is issued, replacing periodic after-the-fact reporting with a continuous, real-time data exchange.
DRR (Digital Reporting Requirements)
Digital Reporting Requirements (DRR) are the ViDA pillar that, from 1 July 2030, obliges EU businesses to issue structured EN 16931 e-invoices and report transaction data to tax authorities in near real time for cross-border intra-Community B2B and B2G trade, replacing recapitulative statements.
EN16931
EN16931 is the European standard for electronic invoicing that defines the semantic data model and business rules all compliant e-invoices must follow.
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Business Terms (BT)
EN16931 semantic data model fields like BT-1, BT-10, BT-46
BT-1 Invoice Number
BT-1 is the unique sequential identifier assigned to an invoice by the seller, required in every EN 16931 e-invoice.
BT-10 Buyer Reference
BT-10 is a text field in the EN 16931 semantic model where the buyer's reference identifier — such as a purchase order number, project code, or routing ID — is carried on the invoice. Optional in EN 16931, but mandatory in key CIUS profiles like XRechnung and Peppol BIS 3.0.
BT-2 Invoice Issue Date
BT-2 is the date when the invoice was issued by the seller, mandatory in every EN 16931 e-invoice.
BT-24 Specification Identifier
BT-24 is the mandatory EN 16931 field that declares which specification — the base standard, a CIUS (like XRechnung or Peppol BIS), or an extension — an invoice claims to conform to. Validators use it to choose which rule set to apply, so an incorrect value leads to the wrong validation or outright rejection.
BT-31 Seller VAT Identifier
BT-31 is the seller's VAT registration number, required when the invoice includes VAT and essential for EU intra-community transactions.
BT-34 Seller Electronic Address
BT-34 identifies the seller's electronic address to which application-level responses (such as invoice response messages) may be delivered. In Peppol, this is the seller's endpoint ID used for network routing.
BT-46 Buyer Identifier
BT-46 is an identifier for the buyer, such as a registration number, that helps uniquely identify the purchasing organization.
BT-48 Buyer VAT Identifier
BT-48 is the buyer's VAT registration number, required for intra-community supplies and reverse charge transactions in EU e-invoicing.
BT-49 Buyer Electronic Address
BT-49 identifies the buyer's electronic address to which the invoice is delivered. In Peppol, this is the buyer's endpoint ID — the primary field used for invoice routing across Access Points.
BT-5 Invoice Currency Code
BT-5 is the currency code for all monetary amounts in the invoice, using ISO 4217 three-letter codes like EUR, USD, or GBP.
BT-63 Seller Tax Registration
BT-63 is the seller's tax registration identifier used in countries where a tax registration separate from VAT exists, such as Germany's Steuernummer.
Business Groups (BG)
EN16931 structural groups like BG-4 Seller, BG-7 Buyer
BG-4 Seller
BG-4 is the EN 16931 business group that contains all information identifying and describing the seller (supplier) of goods or services on the invoice.
BG-7 Buyer
BG-7 is the EN 16931 business group that contains all information identifying and describing the buyer (customer) of goods or services on the invoice.
Standards & Formats
EN16931, Peppol BIS, XRechnung, ZUGFeRD, etc.
CIUS (Core Invoice Usage Specification)
A country- or sector-specific customization of the EN 16931 European e-invoicing standard that restricts or refines the core data model without breaking interoperability. Examples include XRechnung (Germany), Peppol BIS 3.0, and CIUS-IT (Italy).
EN16931
EN16931 is the European standard for electronic invoicing that defines the semantic data model and business rules all compliant e-invoices must follow.
Factur-X
Factur-X is the French name for the ZUGFeRD hybrid e-invoice format that embeds structured XML inside a PDF, enabling both human and machine readability.
FatturaPA
FatturaPA is Italy's national e-invoice format required for all B2B and B2G invoicing through the SDI (Sistema di Interscambio) platform.
Hybrid invoice
An invoice that bundles a human-readable PDF and a structured XML representation of the same data into a single file. The PDF is for people; the embedded XML is for software. ZUGFeRD and Factur-X are the two flagship hybrid formats; both use PDF/A-3 as the carrier.
OASIS UBL (Universal Business Language)
OASIS UBL is the open library of standard XML business documents — invoices, orders, despatch advices, catalogues, and more — published by OASIS as an ISO/IEC standard (19845:2015) and used as the XML syntax behind Peppol BIS, EN 16931, and most European e-invoicing CIUSes.
PDF/A-3
An ISO-standardized archival PDF format (ISO 19005-3) that allows embedding files of any type — including XML invoice data. It is the container format that makes ZUGFeRD and Factur-X hybrid invoices possible.
Peppol
Peppol is a European e-invoicing network that enables businesses to exchange electronic documents across borders using a standardized format and secure infrastructure.
Peppol BIS Billing 3.0
Peppol BIS Billing 3.0 is the specific Peppol Business Interoperability Specification for invoices and credit notes — a CIUS of EN 16931 expressed in OASIS UBL 2.1, validated by Schematron, and the de-facto B2G/B2B billing format on the Peppol network.
XRechnung
XRechnung is Germany's national CIUS (Core Invoice Usage Specification) that extends EN16931 with German-specific requirements for B2G e-invoicing.
ZUGFeRD
ZUGFeRD is a German hybrid e-invoice format that embeds structured XML data inside a PDF/A-3 document, making invoices both human-readable and machine-processable.
Infrastructure & Systems
Peppol network, SDI, Chorus Pro, KSeF, etc.
Chorus Pro
Chorus Pro is France's government platform for receiving and processing B2G e-invoices, mandatory for all invoices to French public entities.
Four Corner Model
The Four Corner Model is the federated network architecture used by Peppol, where invoices travel from sender through two intermediary Access Points to the receiver.
KSeF
KSeF (Krajowy System e-Faktur) is Poland's national e-invoice system that will become mandatory for all B2B invoicing in February 2026.
Nemhandel
Denmark's national e-invoicing and e-procurement infrastructure, run by the Danish Business Authority. Its registry (NHR) doubles as a Peppol SMP, and the network is migrating from the OIOUBL format to a localised Peppol BIS 4 profile branded NemHandel BIS 4.
OpenPeppol
OpenPeppol AISBL is the Belgian non-profit association that owns, governs, and develops the Peppol network — publishing the BIS specifications, code lists, and validation artefacts, and accrediting Peppol Authorities and Service Providers worldwide.
Peppol Access Point
A Peppol Access Point is a certified service provider that connects businesses to the Peppol network, handling message routing, AS4 transport, SMP registration, and delivery receipts.
PPF (Portail Public de Facturation)
The French government's public e-invoicing portal that serves as the central directory and data concentrator for France's mandatory B2B e-invoicing reform launching September 2026.
SDI (Sistema di Interscambio)
SDI is Italy's central government platform that receives, validates, and routes all electronic invoices for both B2B and B2G transactions.
Verifactu
Spain's certified invoicing system operated by the AEAT (tax agency) that requires all billing software to produce tamper-evident, hash-chained invoice records — with optional real-time submission to the tax authority.
VIES (VAT Information Exchange System)
The European Commission's federated lookup service for validating intra-EU VAT numbers. VIES does not hold a central database — it forwards each query to the issuing Member State's tax administration and returns the live response. Frequently confused with Peppol participant lookup; the two solve different problems.
Technical Concepts
schemeID, EndpointID, AS4, XAdES, etc.
CTC (Continuous Transaction Controls)
Continuous Transaction Controls (CTC) are tax-compliance regimes in which transaction data is submitted to, or cleared by, the tax authority at or near the moment an invoice is issued, replacing periodic after-the-fact reporting with a continuous, real-time data exchange.
Digital signature (e-invoicing)
A cryptographic signature applied to an e-invoice (or its XML/PDF carrier) to guarantee authenticity of origin and integrity of content. In several EU CTC regimes — notably Italy's SDI and France's Chorus Pro — a qualified or advanced electronic signature is mandatory; in EN 16931 itself it is optional.
Interoperability framework
A coordinated set of specifications, code lists and governance rules that lets independently built systems exchange e-invoices reliably. In EU e-invoicing the canonical example is the Peppol Interoperability Framework, which combines a technical architecture with binding legal agreements.
PDF/A-3
PDF/A-3 (ISO 19005-3) is an archival PDF format that allows embedded file attachments, making it the required container format for ZUGFeRD and Factur-X hybrid e-invoices.
Post-Audit Model
The traditional VAT compliance model where invoices are exchanged privately between seller and buyer, and the tax authority only inspects them during periodic or triggered audits. It is the model that Continuous Transaction Controls (CTC) — clearance and real-time reporting — are progressively replacing.
QR code (e-invoice)
A 2D barcode embedded on or alongside an electronic invoice that encodes a compact, machine-readable summary of the invoice — typically issuer VAT, total, VAT amount, timestamp, and a cryptographic hash. Mandatory in several CTC regimes (notably Saudi Arabia ZATCA and India), optional in most EU formats.
Real-Time Reporting
A Continuous Transaction Controls (CTC) model in which invoice data is transmitted to the tax authority within minutes or hours of invoice issuance — but after the invoice has already been exchanged with the buyer. Unlike clearance, real-time reporting does not block or pre-approve the invoice; it runs in parallel.
Schematron
Schematron is an XML-based validation language that checks business rules in e-invoices using XPath expressions, producing specific error codes when conditions fail.
Two-corner model
A direct, point-to-point e-invoicing exchange between exactly two parties — sender and receiver — without intermediaries. The pre-Peppol baseline: bespoke EDI agreements, custom mappings, and one connection per trading partner. Largely superseded by the four-corner model for open networks, but still common inside closed supply chains.
XML Schema (XSD)
The W3C standard for describing the structure, data types, and constraints of an XML document. XSD is the first validation layer in any e-invoice pipeline — does the file have the right elements, in the right order, with the right types? Schematron handles business rules on top; both UBL 2.1 and CII D16B ship authoritative XSD schemas.
XPath
A W3C query language for addressing parts of an XML document by path expressions. In EU e-invoicing, XPath is the glue: every Schematron rule, every XSLT mapping, and every "the element at this location is wrong" error message ultimately speaks XPath. ERP developers cannot debug EN 16931 validation without reading it.
XSLT
A W3C language for transforming XML documents into other XML, HTML, or text. In EU e-invoicing, XSLT is the engine that compiles Schematron rules for fast runtime validation, renders UBL or CII invoices into human-readable HTML or PDF (the KoSIT XRechnung visualization toolchain), and converts legacy ERP exports into EN 16931 syntaxes.
Business Concepts
Credit notes, reverse charge, self-billing, etc.
Archiving requirements (e-invoice)
The legal obligations governing how long electronic invoices must be retained, in what format, and with what guarantees of authenticity, integrity, and legibility. The EU baseline is set by Article 247 of the VAT Directive (2006/112/EC); each Member State sets the actual period and storage rules. For an ERP vendor, archiving is rarely six years and never just "keep a PDF."
DRR (Digital Reporting Requirements)
Digital Reporting Requirements (DRR) are the ViDA pillar that, from 1 July 2030, obliges EU businesses to issue structured EN 16931 e-invoices and report transaction data to tax authorities in near real time for cross-border intra-Community B2B and B2G trade, replacing recapitulative statements.
e-Reporting
France's mandatory obligation to electronically report transaction data (B2C sales, cross-border transactions) to the tax authority via the PPF — a parallel track to e-invoicing that covers transactions outside the domestic B2B scope.
Evidence Pack
An Evidence Pack is Invoice Navigator's structured compliance certificate that documents the complete validation, remediation, and revalidation chain for an e-invoice.
Mandate phases
The staged timetables by which EU Member States introduce mandatory e-invoicing and digital reporting, typically rolling from large enterprises down to SMEs, and from receive-capability to issue-obligation. Understanding the phase calendar is the difference between a working go-live and a missed deadline.
OSS (One-Stop Shop)
An EU VAT scheme that lets a business declare and pay VAT on cross-border B2C supplies across all member states through a single quarterly return in one country, instead of registering for VAT in each. It is being broadened under ViDA's Single VAT Registration package.
Tax point (VAT point date)
The date on which VAT becomes chargeable on a supply — the 'time of supply'. It can differ from the invoice date and is carried in EN 16931 as BT-7 (VAT point date) or, alternatively, BT-8 (VAT point date code).
UN/CEFACT
The United Nations Centre for Trade Facilitation and Electronic Business — the UNECE intergovernmental body that produces the Cross Industry Invoice (CII), the second of the two XML syntaxes accepted by EN 16931. UN/CEFACT also publishes the Core Component Library that underpins CII, ZUGFeRD, Factur-X, and most non-UBL e-business standards used in Europe.
ViDA (VAT in the Digital Age)
ViDA is the EU's VAT in the Digital Age package, adopted in March 2025, which makes structured e-invoicing and near-real-time digital reporting the default for cross-border B2B trade and modernises VAT rules for the platform economy and single VAT registration.
Country Identifiers
KVK, Leitweg-ID, SIRET, NIP, etc.
Codice SDI
The Codice SDI (Codice Destinatario) is a 7-character alphanumeric code that routes FatturaPA invoices to the correct recipient through Italy's SDI system.
DUNS Number (D-U-N-S)
A 9-digit business identifier issued by Dun & Bradstreet to a legal entity or location. Registered in the ISO/IEC 6523 ICD registry under code 0060, it is a valid Peppol participant/electronic-address scheme for routing e-invoices.
Endpoint ID
The Endpoint ID is the unique identifier that locates a business on the Peppol network, combining a scheme ID with a national business registration number.
Enterprise Number (Belgium)
The KBO/BCE enterprise number is a unique 10-digit identifier assigned to every business entity registered in Belgium, used as the primary business identifier in Belgian e-invoicing.
GLN (Global Location Number)
A 13-digit GS1 identifier that uniquely identifies a legal entity, function, or physical location — widely used as a Peppol participant ID under ISO 6523 scheme 0088, particularly in retail, healthcare, and logistics.
KVK Number
The KVK number is an 8-digit Dutch Chamber of Commerce registration number that uniquely identifies businesses registered in the Netherlands, widely used as the primary Peppol identifier.
LEI (Legal Entity Identifier)
A 20-character ISO 17442 code that uniquely and globally identifies a legal entity. Administered by GLEIF and issued by accredited LOUs, it is a valid Peppol participant/electronic-address scheme (code 0199) for routing e-invoices.
Leitweg-ID
A structured routing identifier used in German public-sector e-invoicing to direct XRechnung invoices to the correct government entity and internal department. Mapped to the BT-10 (Buyer Reference) field.
NIF/CIF
NIF and CIF are Spanish tax identification numbers — NIF for individuals and CIF for companies — required on all Spanish e-invoices.
NIP
NIP is the Polish tax identification number (Numer Identyfikacji Podatkowej), a 10-digit code required for all B2B e-invoicing through KSeF.
OVT-tunnus (Finland)
The Finnish electronic invoicing address — a 12-to-17-digit identifier built from the prefix 0037, the company's Y-tunnus (business ID), and an optional 5-character suffix. OVT codes are the routing keys for Finnish e-invoicing and are used both in the national e-invoice network and as Peppol participant identifiers under ICD scheme 0216.
Partita IVA
The Italian VAT identification number — an 11-digit numeric code issued by the Agenzia delle Entrate that identifies a business or self-employed professional for VAT purposes and is mandatory on every invoice routed through the SDI.
Peppol ID
A Peppol ID is a participant identifier on the Peppol network, composed of an ISO 6523 scheme ID and a national business registration number.
Scheme ID
A Scheme ID is a code that identifies the type of business identifier used in an e-invoice, such as a VAT number, chamber of commerce registration, or national enterprise number.
SIREN
The 9-digit French business identification number issued by INSEE that identifies a legal entity as a whole — the root identifier from which SIRET establishment numbers and the French VAT number are derived.
SIRET Number
SIRET is a 14-digit French establishment identification number (SIREN 9 + NIC 5) that uniquely identifies a specific business location, used in Factur-X and PDP-based e-invoicing.
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