E-Invoicing Technical Guide: Formats, Networks & Standards

Understanding the regulatory landscape of European e-invoicing is only the first step. To successfully implement compliant solutions, businesses need to grasp the technical infrastructure underlying electronic invoice exchange: data formats, transport networks, and VAT compliance elements.

This technical guide demystifies the complexity, providing clear explanations of UBL, Peppol, GOBL, and other essential standards. Whether you're a technical implementer or a business decision-maker, this article equips you with the knowledge to make informed choices about your e-invoicing solution.

New to e-invoicing mandates? Start with our Complete Guide to European E-Invoicing Mandates 2025-2027 to understand regulatory requirements before diving into technical details.

E-Invoicing Formats: The Language of Digital Invoices

Different formats serve different purposes and regional requirements. Your NetSuite solution must support the formats required in your operating countries.

UBL 2.1 (Universal Business Language)

UBL represents the most widely adopted e-invoicing format globally, providing the foundation for interoperable business document exchange.

What is UBL?

Developed by OASIS (Organization for the Advancement of Structured Information Standards), UBL 2.1 provides comprehensive semantic models for business documents including invoices, credit notes, purchase orders, and more.

Technical characteristics:

• XML-based format with standardized structure
• Extensible framework allowing customization while maintaining core compatibility
• Rich semantic model covering complex business scenarios
• International standard (ISO/IEC 19845)

Where it's used:

Belgium, Netherlands, and many other European countries use UBL as their standard e-invoicing format. The Peppol network primarily uses UBL BIS (Business Interoperability Specifications) Billing 3.0, a UBL subset optimized for cross-border transactions.

Key UBL elements:

• Invoice header: Supplier and buyer information, invoice date, payment terms
• Invoice lines: Item descriptions, quantities, unit prices, line totals
• Tax information: VAT rates, exemption codes, tax amounts
• Totals and summaries: Line totals, tax totals, invoice total
• Payment information: Bank details, payment references

Advantages:

• Globally recognized standard
• Extensive tooling and libraries available
• Strong support for complex business scenarios
• Core of Peppol network infrastructure

Considerations:

• XML verbosity can increase file sizes
• Complexity may be overkill for simple invoices
• Proper validation required to ensure compliance

UN/CEFACT CII (Cross Industry Invoice)

Developed by the United Nations Centre for Trade Facilitation and Electronic Business, CII provides an alternative to UBL with particularly strong adoption in German-speaking countries.

What is CII?

UN/CEFACT CII is an XML-based format designed for cross-industry use, focusing on supply chain and trade facilitation. The invoice variant (specifically D16B SCRDM CII) is widely used for e-invoicing.

Technical characteristics:

• XML-based with hierarchical structure
• Industry-neutral design applicable across sectors
• UN pedigree ensuring international governance
• Flexible schema accommodating various business models

Where it's used:

France accepts CII as one of its approved formats alongside UBL and Factur-X. Germany also supports CII, particularly for businesses with existing UN/CEFACT infrastructure. Growing adoption in international trade scenarios.

Key advantages:

• Strong support in Germanic countries
• Designed for complex supply chain scenarios
• International UN backing ensures longevity
• Good for businesses with existing UN/CEFACT implementations

Compared to UBL:

• Different XML structure but similar semantic coverage
• May be preferred where UN/CEFACT standards already in use
• Slightly different tooling ecosystem
• Both achieve same compliance objectives

Factur-X / ZUGFeRD: The Hybrid Approach

This innovative hybrid format combines structured machine-readable data with human-readable PDF in a single file, bridging the gap between traditional and digital invoicing.

What is Factur-X?

Factur-X (the French standard) and ZUGFeRD (the German standard) are essentially identical formats with minor regional variations. The format embeds structured XML data (using CII format) inside a PDF/A-3 document.

How it works:

1. The PDF provides human-readable invoice presentation
2. Embedded XML contains machine-readable structured data
3. Single file serves both human viewing and automated processing
4. PDF ensures visual consistency across systems

Technical characteristics:

• PDF/A-3 container with embedded XML attachment
• CII format for structured data
• Multiple conformance levels: MINIMUM, BASIC WL, BASIC, EN 16931, EXTENDED
• Backward compatibility with PDF readers (XML ignored if not supported)

Where it's used:

France explicitly supports Factur-X as an approved format for its e-invoicing mandate. Germany recognizes ZUGFeRD. Growing adoption in countries seeking gradual transition from paper/PDF to structured e-invoicing.

Conformance levels:

MINIMUM: Basic invoice identification (invoice number, date, amount)
BASIC WL: Adds line-level information without item details
BASIC: Adds basic item descriptions
EN 16931: Full compliance with European e-invoicing standard
EXTENDED: Additional business-specific fields

Advantages:

• Dual-purpose file serves human and machine needs
• Easier adoption for businesses transitioning from PDF
• Visual consistency maintained across systems
• Backward compatible with existing PDF workflows

Considerations:

• Larger file sizes than pure XML
• PDF generation adds complexity
• Requires proper PDF/A-3 compliance
• XML must stay synchronized with PDF content

GOBL (Invopop's Open-Source Format)

GOBL (Global Open Business Language) is Invopop's innovative open-source format designed for maximum flexibility and extensibility.

What makes GOBL different?

Rather than being a final invoice format, GOBL serves as a universal intermediate format that can convert to any required regional standard (UBL, CII, FatturaPA, FA(3), etc.).

The GOBL approach:

1. Your NetSuite system generates data in GOBL format
2. GOBL document contains comprehensive invoice information
3. Invopop platform converts GOBL to required destination format
4. Single integration supports multiple countries and formats

Technical characteristics:

• JSON-based (not XML) for modern developer experience
• Highly extensible with custom fields and extensions
• Open-source with transparent conversion logic
• Multi-format conversion to any regional standard

Architecture advantages:

Single integration point: Instead of building separate integrations for UBL, CII, FatturaPA, FA(3), etc., you integrate once with GOBL.

Future-proof: New country formats require only Invopop platform updates, not changes to your NetSuite integration.

Transparent conversions: Open-source conversion logic lets you understand exactly how data transforms.

Developer-friendly: JSON format is easier to work with than complex XML schemas.

Where it's used:

GOBL is the core format for Invopop's e-invoicing platform. Organizations using Invopop (including Novutech's NetSuite e-invoicing solution) benefit from GOBL's flexibility without needing to understand the complexities of each destination format.

Learn how Novutech implements GOBL-based e-invoicing for NetSuite →

Country-Specific Formats

Some countries require formats specific to their regulatory environment.

FatturaPA (Italy):

• XML format specific to Italian requirements
• Required for SDI (Sistema di Interscambio) clearance platform
• Includes Italian-specific fields and business rules
• Mandatory since 2019 for B2B and B2G transactions

FA(3) (Poland):

• Format for KSeF (Krajowy System e-Faktur) clearance system
• Replaces previous FA(2) format
• Uses KSeF 2.0 API
• Required validation before legal recognition

VeriFactu Elements (Spain):

• QR code data for verification
• Software certification requirements
• Traceability information
• Anti-fraud compliance elements

Format selection strategy: Choose solutions that support formats required in your operating countries while providing flexibility for future expansion.

The Peppol Network: Interoperable E-Invoice Exchange

The Peppol network provides the infrastructure enabling interoperable e-invoicing across borders without requiring direct connections between trading partners.

What is Peppol?

Peppol (Pan-European Public Procurement OnLine) is a set of specifications and a network infrastructure enabling businesses to exchange electronic documents (invoices, orders, etc.) in a standardized, interoperable way.

Key concept: Peppol is both a technical specification (how to exchange documents) and a network of certified service providers (who facilitates the exchange).

How Peppol Works

The Four-Corner Model:

Corner 1 - Sender (Your Company):
You create an invoice in your ERP system (NetSuite) using your internal processes and formats.

Corner 2 - Sender's Access Point:
Your certified Peppol Access Point converts your invoice to Peppol format (UBL BIS Billing 3.0) and handles transmission.

Corner 3 - Receiver's Access Point:
The recipient's Access Point receives the Peppol-formatted invoice and converts it to their required format.

Corner 4 - Receiver (Your Customer):
Your customer receives the invoice in their system in a format they can process.

The magic of Peppol: You never need direct integration with your trading partners. The Access Points handle all interoperability.

Peppol Infrastructure Components

Access Points:
Certified service providers authorized to send and receive documents on the Peppol network. Examples include Invopop, Storecove, Basware, Pagero, and many others.

SMP (Service Metadata Publisher):
Each Access Point operates an SMP containing information about which documents a participant can receive and how to reach them.

SML (Service Metadata Locator):
Central directory that points to the correct SMP for each participant, enabling dynamic routing across the network.

Document Specifications:
Standardized document formats (BIS - Business Interoperability Specifications) like BIS Billing 3.0 for invoices.

Peppol ID Structure

Every Peppol participant requires a unique Peppol ID (also called Peppol Participant Identifier) for routing documents.

Format: [scheme]::[identifier]

Examples:

• Belgium: 0208:0123456789 (scheme 0208 = Belgian Enterprise Number)
• Netherlands: 0106:12345678 (scheme 0106 = Dutch KVK number)
• Norway: 0192:987654321 (scheme 0192 = Norwegian organization number)

How routing works:

1. You want to send invoice to customer with Peppol ID 0208:0123456789
2. Your Access Point queries the SML for this ID
3. SML returns the SMP location for this participant
4. Your Access Point queries the SMP for routing details
5. Invoice is transmitted to the customer's Access Point
6. Customer's Access Point delivers to their system

Peppol Coverage and Adoption

Operating in 40+ countries:
All EU member states, UK, Norway, Switzerland, Singapore, Australia, New Zealand, Japan, USA (growing), and others.

Interoperability guarantee:
Any certified Access Point can communicate with any other Access Point regardless of provider. This true interoperability is Peppol's core value.

Mandatory for:

• Belgium B2B e-invoicing (January 2026)
• Nordic countries B2G procurement
• Germany (alongside other options)
• Growing list of EU countries

Advantages for businesses:

• No direct integrations with trading partners required
• Cross-border compatibility built-in
• Provider choice - switch Access Points if needed
• Future-proof as more countries adopt Peppol

Peppol vs. Clearance Models

Peppol (Decentralized Exchange):

• Invoices transmitted directly between trading partners via Access Points
• Government may receive reporting data separately
• No invoice blocking by government validation
• Business continuity maintained even if government systems unavailable

Clearance (Centralized Validation):

• Every invoice must pass through government platform
• Validation occurs before invoice gains legal status
• Invoice transmission to buyer only after government approval
• Maximum government visibility but dependency on platform availability

Countries using Peppol: Belgium, Netherlands, Nordic countries, Germany (option)

Countries using Clearance: Italy, Poland, Spain (partial), Turkey, Romania

Understand regulatory models by country →

Continuous Transaction Controls (CTC)

CTC represents a fundamental shift in how tax authorities monitor economic activity.

What is CTC?

Continuous Transaction Controls enable tax authorities to receive transactional data in real-time or near-real-time, moving from periodic tax reporting to continuous monitoring.

Traditional VAT reporting:
Businesses file quarterly or monthly VAT returns summarizing all transactions for the period.

CTC approach:
Tax authorities receive data for every transaction as it occurs, enabling real-time monitoring and rapid fraud detection.

Clearance vs. Reporting Models

Clearance Model (Italy, Poland):

Process:

1. Supplier creates invoice
2. Invoice sent to government clearance platform
3. Platform validates format, content, VAT calculations
4. Platform assigns unique clearance ID and timestamp
5. Only after clearance can invoice be sent to buyer
6. Invoice gains legal recognition through clearance process

Characteristics:

• Government validation required before invoice completion
• Invoice cannot be sent to buyer until cleared
• Provides maximum government visibility
• Creates dependency on government system availability
• Risk of processing delays if platform issues occur

Reporting Model (France, Spain):

Process:

1. Supplier creates invoice
2. Invoice sent directly to buyer
3. Simultaneously, transaction data reported to tax authorities
4. Government monitors but doesn't block invoice exchange

Characteristics:

• Invoices transmitted directly to buyers
• Government receives reporting data separately
• Greater resilience - business not blocked by government issues
• Maintains business continuity
• Balances oversight with operational flexibility

Government Validation in Clearance Systems

What gets validated:

Format compliance: Is the invoice in the correct XML structure with required fields?

VAT calculation accuracy: Do line-level VAT amounts add up correctly? Is the total VAT calculated properly?

Party identification validity: Are supplier and buyer VAT numbers valid and active?

Business rule compliance: Does the invoice meet country-specific requirements?

Upon successful validation:

• Unique identifier assigned (clearance ID, KSeF number, etc.)
• Official timestamp recorded
• Immutable audit trail created
• Legal invoice status granted

If validation fails:

• Invoice rejected with error details
• Must be corrected and resubmitted
• No legal invoice exists until cleared
• Buyer should not pay until valid invoice received

VAT Compliance Elements

Proper VAT treatment is critical for e-invoice compliance and acceptance by both receiving systems and tax authorities.

VAT Codes and Peppol Tax Mapping

NetSuite's native tax codes must be mapped to Peppol-compliant tax codes for e-invoice transmission. This mapping ensures the receiving system and tax authorities correctly interpret the VAT treatment applied to each line item.

Common Peppol tax code categories:

S (Standard): Standard VAT rate for regular goods and services
Z (Zero rated): Special zero-rated goods (different from exempt)
E (Exempt): Goods/services exempt from VAT by local law
G (Export): Sale of goods outside the European Economic Area
K (Intra-Community supply): Sale of goods within the EEA to VAT-registered businesses
AE (Reverse charge): VAT paid by customer instead of supplier
O (Out of scope): Transactions where VAT doesn't apply (e.g., some international services)

Mapping example:

Your NetSuite tax code "FR-VAT-20" (French standard VAT) maps to:

• Peppol category: S (Standard)
• Rate: 20%
• Country: FR

Your NetSuite tax code "FR-VAT-EXEMPT-ART293B" maps to:

• Peppol category: E (Exempt)
• Exemption reason code: VATEX-EU-O
• Country: FR

VAT Rate Categories

Different rate categories must be distinguished in e-invoices to ensure proper tax treatment.

Standard Rate:
The default VAT rate in each country (e.g., 21% in Belgium, 20% in France, 19% in Germany).

Intermediate Rate:
Some countries have multiple reduced rates (e.g., France has 10% intermediate rate for restaurants, renovations).

Reduced Rate:
Lower rate for specific goods/services (e.g., food, books, pharmaceuticals). Rate percentages vary by country.

Super-Reduced Rate:
Very low rate for essential goods (e.g., 2.1% in France for medicines, 4% in Spain for basic necessities).

Zero Rate:
0% VAT but with right to reclaim input VAT (different from exempt). Common for exports, books in some countries.

Parking Rate:
Special rate for used goods under margin scheme in some countries.

Why proper categorization matters:

• Tax authorities validate rate correctness
• Buyers need accurate VAT for their own accounting
• Incorrect rates can cause invoice rejection
• Compliance audits scrutinize VAT treatment

VAT Exemption Codes (Vatex)

When an invoice line is VAT-exempt, a standardized exemption code explains why. These codes ensure transparency and enable automated validation.

Key Vatex codes:

VATEX-EU-AE (Reverse charge):
Domestic reverse charge where buyer accounts for VAT (B2B construction, telecommunications, etc.)

VATEX-EU-G (Export outside EU):
Goods exported outside the European Union (zero-rated for VAT purposes)

VATEX-EU-IC (Intra-Community supply):
Goods sold to VAT-registered business in another EU member state

VATEX-EU-O (Not subject to VAT):
Services or transactions outside the scope of VAT (e.g., certain financial services)

VATEX-EU-132 (Financial services):
Specific exemption for financial and insurance services under Article 135 VAT Directive

VATEX-EU-148 (Medical services):
Healthcare services exempt under Article 132 VAT Directive

Country-specific codes:
Many countries have additional exemption codes for specific scenarios (second-hand goods, works of art, small businesses under simplified schemes, etc.)

Proper usage in e-invoices:

For exempt line item:

• Tax category: E (Exempt)
• Tax percentage: 0%
• Exemption reason code: Appropriate Vatex code
• Exemption reason text: Human-readable explanation (optional but recommended)

Example:

<cac:TaxCategory>

  <cbc:ID>E</cbc:ID>

  <cbc:Percent>0</cbc:Percent>

  <cbc:TaxExemptionReasonCode>VATEX-EU-IC</cbc:TaxExemptionReasonCode>

  <cbc:TaxExemptionReason>Intra-Community supply to FR12345678901</cbc:TaxExemptionReason>

</cac:TaxCategory>

Reverse Charge Mechanism

The reverse charge mechanism shifts VAT liability from supplier to buyer in specific scenarios.

When it applies:

• Cross-border B2B supplies within EU (intra-Community supplies)
• Certain domestic supplies (construction, waste, telecommunications, etc.)
• Import of services from outside EU

How it works in e-invoices:

Supplier perspective:

• Invoice shows 0% VAT
• Tax category: AE (Reverse charge)
• Clear indication that buyer must account for VAT
• Invoice text states reverse charge applies

Buyer perspective:

• Records both output VAT (as if they charged it) and input VAT (as if they paid it)
• Net effect typically zero for fully VAT-registered businesses
• Must account for VAT in their VAT return

E-invoice requirements:

• Correct tax category code (AE)
• Clear reverse charge text
• Buyer's VAT number included
• Reference to applicable legal provision

Learn how to implement proper VAT handling in NetSuite →

Format Selection Strategy

Choosing the right formats for your organization depends on multiple factors.

Consider Your Operating Countries

Belgium mandate: UBL 2.1 via Peppol
France mandate: UBL, CII, or Factur-X via PPF platforms
Germany requirements: UBL or CII via Peppol or other methods
Poland mandate: FA(3) via KSeF clearance
Italy mandate: FatturaPA via SDI clearance

Multi-country operations: Need solution supporting multiple formats or using intermediate format (like GOBL) that converts to required standards.

Evaluate Your Technical Capabilities

Strong XML expertise: Direct UBL or CII implementation feasible
Limited technical resources: Consider solutions abstracting format complexity
Existing Peppol relationships: Leverage current Access Point connections
Legacy systems: May need middleware for format conversion

Balance Flexibility vs. Simplicity

Maximum flexibility: GOBL-based solution (single integration, multi-format output)
Country-specific optimization: Native format implementations for each country
Gradual transition: Factur-X for moving from PDF to structured data
Simplicity: Pre-built solutions handling format complexity

Next Steps: From Understanding to Implementation

Understanding technical standards is essential, but successful e-invoicing requires proper implementation in your ERP system.

NetSuite E-Invoicing Solutions: Complete Implementation Guide →
Discover how to implement e-invoicing in NetSuite, compare solution providers (Invopop, Avalara, 4CEE, Zone, Banqup), and calculate your ROI.

European E-Invoicing Mandates Overview →
Review regulatory requirements and compliance timelines for Belgium, France, Poland, Germany, and other European countries.

Conclusion

The technical infrastructure underlying European e-invoicing is complex, but understanding key concepts—formats, networks, and standards—empowers informed decision-making.

Whether you choose UBL's widespread adoption, CII's supply chain focus, Factur-X's hybrid approach, or GOBL's flexibility, success depends on matching technical capabilities to business requirements and regulatory obligations.

Novutech's e-invoicing expertise combines technical knowledge with practical NetSuite implementation experience, helping businesses navigate complexity while maximizing operational benefits.

Ready to implement e-invoicing in NetSuite? Contact our technical experts

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