Access Point (Peppol)

Peppol Access Point / Service Provider

A Peppol Access Point is a certified service provider that connects businesses to the Peppol network. Access Points handle the transmission, validation, and delivery of e-invoices using the AS4 protocol. Every business needs an Access Point to send or receive Peppol documents — similar to how an email provider handles email delivery. InvoStaq operates as a certified Peppol Access Point with AI-powered pre-validation.

AS4

Applicability Statement 4

AS4 is the messaging protocol used in the Peppol network for secure, reliable document exchange between Access Points. Based on OASIS ebMS 3.0, AS4 provides message encryption (TLS), digital signatures, message acknowledgments, and reliable delivery with retry mechanisms. All Peppol Access Points, including InvoStaq, must implement AS4 for network communication.

BIS Billing 3.0

Peppol Business Interoperability Specification for Billing

BIS Billing 3.0 is the Peppol specification for invoicing built on top of EN 16931 and UBL 2.1. It defines additional business rules, validation artefacts, and code lists specific to the Peppol network. An invoice that passes BIS Billing 3.0 validation is guaranteed to be accepted by any Peppol endpoint worldwide. InvoStaq validates every invoice against the full BIS Billing 3.0 rule set.

CII

Cross-Industry Invoice (UN/CEFACT)

CII (Cross-Industry Invoice) is an XML-based invoice format developed by UN/CEFACT. It is the alternative to UBL accepted under the EN 16931 standard. CII is particularly popular in France (Factur-X) and Germany (ZUGFeRD). InvoStaq supports both UBL and CII formats and can automatically convert between them based on the recipient's requirements.

CTC

Continuous Transaction Control

Continuous Transaction Control (CTC) is a tax compliance model where tax authorities receive invoice data in real-time or near-real-time, rather than through periodic reporting. CTC comes in several variants: post-audit (traditional), real-time reporting (data sent alongside invoice), pre-clearance (government must approve before delivery), and decentralised CTC (validation delegated to certified providers). InvoStaq supports all CTC variants.

Chorus Pro

Chorus Pro (France)

Chorus Pro is France's government portal for e-invoicing, currently mandatory for B2G (business-to-government) transactions. France is implementing a new PPF/PDP model for B2B e-invoicing (mandatory from September 2026) where businesses can choose to route invoices through the government PPF (Portail Public de Facturation) or certified PDPs (Plateformes de Dématérialisation Partenaires). InvoStaq can operate as a PDP-connected platform.

CIUS

Core Invoice Usage Specification

A CIUS (Core Invoice Usage Specification) is a national or sectoral customisation of the EN 16931 standard. Countries create CIUSs to add local business rules while remaining compliant with the European core standard. Examples include XRechnung (Germany), NLCIUS (Netherlands), and Peppol BIS Billing 3.0 (pan-European). InvoStaq's AI engine validates against all major CIUSs.

EN 16931

European Standard on Electronic Invoicing

EN 16931 is the European standard that defines the semantic data model for the core elements of an electronic invoice. Published by CEN (European Committee for Standardization), it ensures that e-invoices contain all required information in a structured format regardless of the syntax used (UBL or CII). All EU public procurement e-invoices must comply with EN 16931, and the ViDA directive will extend this to B2B transactions.

e-Reporting

Electronic Reporting / Digital Reporting Requirements

e-Reporting (or Digital Reporting Requirements / DRR) is the obligation to report transaction data electronically to tax authorities. Under the EU ViDA directive, businesses will need to report cross-border B2B transactions in real-time. e-Reporting can coexist with or replace e-invoicing mandates depending on the country's CTC model.

Four-Corner Model

Peppol Four-Corner Model

The Four-Corner Model is Peppol's standard document exchange architecture. The four corners are: (1) the Sender (e.g. supplier), (2) the Sender's Access Point (e.g. InvoStaq), (3) the Receiver's Access Point, and (4) the Receiver (e.g. buyer). The two Access Points communicate using the AS4 protocol, while businesses interact with their own Access Point through APIs or ERP plugins.

Five-Corner Model

Peppol Five-Corner Model

The Five-Corner Model extends the Four-Corner Model by adding a fifth entity: the tax authority or regulatory clearing house. In this model, the invoice passes through a government system for validation or approval before reaching the buyer. This is the basis for Continuous Transaction Control (CTC) and pre-clearance models used in countries like Saudi Arabia (ZATCA), Italy (SDI), and planned for the EU ViDA directive.

FATOORA

ZATCA E-Invoicing System

FATOORA is Saudi Arabia's national e-invoicing system operated by ZATCA. It requires businesses to generate XML invoices with cryptographic stamps, QR codes containing invoice hashes, and digital signatures. In Phase 2, invoices must be submitted to the Fatoora Portal API for clearance before delivery to the buyer. InvoStaq automates the entire FATOORA workflow including XML generation, cryptographic stamping, and API submission.

FatturaPA

FatturaPA (Italy)

FatturaPA is Italy's mandatory XML format for electronic invoices processed through the SDI (Sistema di Interscambio). It includes specific Italian requirements for tax codes (Codice Fiscale, Partita IVA), payment terms, and regulatory references. Since January 2019, all B2B and B2C invoices in Italy must use this format.

KSeF

Krajowy System e-Faktur (Poland)

KSeF (Krajowy System e-Faktur) is Poland's National e-Invoicing System, scheduled to become mandatory for all businesses in 2026-2027. KSeF requires invoices to be submitted to a central government platform in a structured XML format before delivery. Once submitted, the system assigns a unique KSeF number and timestamp. InvoStaq supports KSeF compliance with automatic format conversion and API integration.

OpenPeppol

OpenPeppol AISBL

OpenPeppol is the international non-profit association that governs the Peppol network. Headquartered in Brussels, Belgium, it manages the Peppol specifications, certifies Access Points and SMPs, maintains the transport infrastructure, and coordinates with national Peppol Authorities worldwide. Any company wanting to become a Peppol Access Point must be certified by OpenPeppol.

Peppol

Pan-European Public Procurement Online

Peppol is an international framework for electronic document exchange, originally developed for public procurement in Europe. It enables businesses and governments to exchange e-invoices, purchase orders, and other documents with any trading partner on the Peppol network through standardised protocols. The network connects 380,000+ endpoints across 39+ countries. InvoStaq is a certified Peppol Access Point.

Pre-Clearance

Pre-Clearance E-Invoicing Model

Pre-clearance is a CTC variant where invoices must be validated and approved by the tax authority or an authorised platform before they can be delivered to the buyer. If an invoice fails validation, it is rejected before it enters the official tax record. Saudi Arabia (via ZATCA FATOORA Phase 2) and Italy (via SDI) use pre-clearance. InvoStaq implements a pre-clearance AI layer that catches errors before submission to these systems.

PPF / PDP

Portail Public de Facturation / Plateforme de Dématérialisation Partenaire

PPF (Portail Public de Facturation) is France's government e-invoicing portal. PDP (Plateforme de Dématérialisation Partenaire) is a certified private platform that can process e-invoices on behalf of the government. Under France's upcoming B2B mandate (September 2026), businesses must route invoices through either the PPF or a certified PDP. PDPs offer additional services like format conversion, validation, and archiving.

Peppol ID

Peppol Participant Identifier

A Peppol ID is a unique identifier assigned to every participant on the Peppol network. It typically consists of a scheme identifier (e.g., 0208 for Belgian enterprises, 9925 for Austrian VAT numbers) and the actual identifier (e.g., VAT number or company registration number). The Peppol ID is used to look up a receiver's Access Point and capabilities via the SMP/SML infrastructure.

SMP

Service Metadata Publisher

The SMP (Service Metadata Publisher) is a registry in the Peppol network that stores metadata about a participant's capabilities — which document types they can receive, which Access Point they use, and which transport protocols are supported. When sending an invoice via Peppol, the sender's Access Point queries the recipient's SMP to determine how to deliver the document.

SML

Service Metadata Locator

The SML (Service Metadata Locator) is the top-level directory in Peppol's infrastructure that maps participant identifiers to their SMP location. It uses DNS to resolve where a participant's metadata is stored. Think of it as the phone book that tells you which registry (SMP) holds information about a specific business.

SDI

Sistema di Interscambio (Italy)

SDI (Sistema di Interscambio) is Italy's government-operated e-invoicing exchange system. Since January 2019, all B2B and B2C invoices in Italy must be routed through the SDI in FatturaPA XML format. The SDI validates the invoice, forwards it to the recipient (via PEC, Peppol, or SDI code), and reports to the tax authority. Italy was the first EU country to mandate universal B2B e-invoicing.

Semantic AI Audit

InvoStaq Semantic AI Audit

Semantic AI Audit is the second layer of InvoStaq's Intelligent E-Invoicing Solution engine, powered by Microsoft Azure AI. While the Syntax AI Guardian checks structural validity, the Semantic AI Audit analyses business logic — verifying tax calculations, validating buyer/seller information against government registries, detecting anomalies, and cross-referencing against country-specific regulations. It processes invoices in under 200 milliseconds.

Syntax AI Guardian

InvoStaq Syntax AI Guardian

Syntax AI Guardian is the first validation layer in InvoStaq's AI engine. It checks invoice documents against structural requirements: XML schema compliance, mandatory field presence, data type validation, code list verification (currency codes, country codes, tax category codes), and Peppol BIS Billing 3.0 business rules. It catches formatting errors before the deeper Semantic AI Audit runs.

Traffic Light Protocol (InvoStaq)

InvoStaq Traffic Light Protocol

The Traffic Light Protocol is InvoStaq's proprietary visual compliance feedback system. Every invoice receives a colour code: Green (fully compliant, submitted successfully), Amber (minor warnings, review recommended but submission allowed), or Red (critical errors, blocked from submission with plain-English explanations). This system ensures no non-compliant invoice ever reaches a tax authority.

UBL

Universal Business Language

UBL (Universal Business Language) is an OASIS standard XML format for business documents including invoices, credit notes, and purchase orders. UBL 2.1 is the primary format used in the Peppol network for e-invoicing. It defines a standardised structure with elements for seller, buyer, line items, tax breakdowns, and payment terms. InvoStaq validates and generates UBL 2.1 documents automatically.

ViDA

VAT in the Digital Age

ViDA (VAT in the Digital Age) is a European Commission directive that will harmonise e-invoicing and digital reporting across all EU member states. Key provisions include mandatory e-invoicing for cross-border B2B transactions (from 2030), real-time Digital Reporting Requirements (DRR), and updated VAT rules for the platform economy. InvoStaq is fully prepared for ViDA compliance with EN 16931 support and multi-country rule engines.

Verifactu

Sistema Verifactu (Spain)

Verifactu is Spain's anti-fraud e-invoicing system introduced under the Ley Crea y Crece law. It requires billing software to generate invoices with cryptographic hashes, sequential chaining (each invoice references the previous one's hash), and real-time or near-real-time reporting to the Spanish Tax Agency (AEAT). Verifactu does not require pre-clearance but ensures tamper-proof invoice records.

VAT Gap

The VAT Gap is the difference between expected VAT revenue (based on economic activity) and actual VAT collected by a government. In 2022, the EU VAT Gap was estimated at €61 billion — approximately 5.3% of expected revenue. E-invoicing mandates and CTC systems are the primary tools governments use to close the VAT Gap by enabling real-time visibility into transactions. InvoStaq helps businesses comply with these mandates while preventing errors that contribute to the gap.

XRechnung

XRechnung (Germany)

XRechnung is Germany's national standard for e-invoicing, implemented as a Core Invoice Usage Specification (CIUS) of EN 16931. It is mandatory for B2G invoicing in Germany. Starting January 2027, Germany will require B2B e-invoicing using EN 16931-compliant formats. XRechnung uses UBL 2.1 and CII syntax with Germany-specific business rules. InvoStaq supports XRechnung generation and validation.

ZATCA

Zakat, Tax and Customs Authority (Saudi Arabia)

ZATCA is Saudi Arabia's tax authority, responsible for the country's e-invoicing mandate known as FATOORA. Phase 1 (generation, effective December 2021) requires businesses to generate and store e-invoices in structured format. Phase 2 (integration, rolling from January 2023) requires real-time API integration with ZATCA's Fatoora Portal for invoice validation and clearance. InvoStaq supports both phases with automated XML signing, QR code generation, and direct API integration.

ZUGFeRD / Factur-X

Zentraler User Guide des Forums elektronische Rechnung Deutschland

ZUGFeRD (Germany) and Factur-X (France) are identical hybrid invoice formats that embed a structured XML (CII format) inside a PDF/A-3 document. This allows human-readable and machine-readable invoice data in a single file. The format supports multiple profiles from basic to extended. ZUGFeRD/Factur-X is widely used in Germany and France and is compliant with EN 16931.