What Is an E-Invoice? Peppol, Formats, and Who Must Use Them

An electronic invoice is not an invoice that arrived electronically. A PDF attached to an email is a picture of an invoice — a human can read it, a machine cannot process it without guessing.

An e-invoice is an invoice issued, transmitted and received in a structured format that allows automatic processing. The distinction is now legal rather than technical: ViDA rewrites the definition in the VAT Directive so that from 1 July 2030, only structured formats qualify as electronic invoices. A PDF stops counting.

Why structure matters

A structured invoice carries typed, addressable fields: supplier VAT number, line quantity, VAT rate, taxable amount per rate. The buyer's system reads them, matches against a purchase order, routes for approval and posts — with no re-keying and no OCR guesswork.

The economics follow directly: fewer errors, faster approval, faster payment, and the ability for tax authorities to verify transactions transaction by transaction rather than through periodic returns. That last point is why governments, not businesses, are driving adoption.

The standard: EN 16931

The European standard EN 16931 defines a semantic data model — what an invoice means: the parties, the identifiers, the totals, the VAT breakdown. It is deliberately not a file format. Two syntaxes carry the model in practice:

• UBL 2.1 (OASIS Universal Business Language) — the common one
• UN/CEFACT CII (Cross Industry Invoice)

On top sit CIUS documents — Core Invoice Usage Specifications — which narrow the standard for a country or network: Peppol BIS Billing 3.0, Germany's XRechnung, Romania's CIUS-RO. A CIUS never adds meaning outside EN 16931; it restricts and mandates within it, which is what keeps cross-border interoperability possible.

Directive 2014/55/EU already made EN 16931 mandatory for B2G invoicing across the EU — every public authority must be able to receive it. B2B is where the national mandates are now arriving.

Peppol: the network

Peppol is not a format — it is a delivery network, and the distinction confuses people constantly.

It works on a four-corner model: sender → sender's access point → receiver's access point → receiver. You connect once to an access point; it can reach every participant on the network. Participants are identified by a Peppol ID (a scheme identifier plus a value, such as a VAT number), discoverable through a distributed service-metadata registry.

Peppol BIS Billing 3.0 is the CIUS that most European exchange uses, and it is what "Peppol invoice" almost always means in practice.

National clearance systems

Several member states require invoices to pass through a government platform before or as they reach the buyer — a fundamentally different model from Peppol's network delivery:

Country	System	Model
Italy	SdI (Sistema di Interscambio)	Clearance — every B2B and B2C invoice via the platform, FatturaPA format
Poland	KSeF	Clearance — FA(3) schema, phased mandatory through 2026
Romania	e-Factura	Clearance — UBL with CIUS-RO, B2B mandatory since 2024
France	Phased 2026–27	Partner platforms (PDP) plus e-reporting
Germany	Phased from 2025	Receiving capability first, issuing obligations later

Under clearance the state sees the invoice as it is issued, not months later on a return. This is where VAT enforcement is heading, and the reason ViDA's digital reporting replaces recapitulative statements entirely from 2030.

What ViDA changes

Council Directive (EU) 2025/516, in force since 14 April 2025:

• Already live: member states may mandate domestic B2B e-invoicing without requesting an EU derogation — which is why national mandates accelerated through 2025 and 2026.
• From 1 July 2030: structured e-invoicing becomes the default for intra-EU B2B, customer acceptance is no longer required for compliant invoices, recapitulative statements are abolished in favour of digital reporting, and two new mandatory particulars appear — the number of the invoice being corrected on a corrective invoice, and the supplier's bank or virtual account identifiers.

Worth noting precisely, because it is widely misreported: the adopted text says "bank account numbers or numbers of virtual accounts … or any other identifiers", not "IBAN", and a payment-date requirement that appeared in the Commission's proposal was dropped.

How Nordlet handles e-invoicing

Invoices are structured data first and documents second, so producing any of these formats is a rendering step rather than a conversion.

Peppol BIS 3.0 — POST /v1/sales/invoices/peppol-xml returns the UBL, and /peppol-send delivers it through an access point. Participant IDs are derived from the partner's Peppol ID, VAT code or registration code, in that order. Credit notes go out as UBL CreditNote documents with type code 381.

Access point resolution checks the company's own access point first and falls back to the platform's built-in one, so a company can bring its own provider or use the operator's without changing anything else.

National formats — /v1/sales/invoices/einvoice-xml renders the format for the company's country: FatturaPA FPR12 for Italy, KSeF FA(3) for Poland (validated against the official XSD), and UBL with the CIUS-RO customization for Romania. /einvoice-send delivers the payload to a bridge endpoint configured per company.

Each renderer returns warnings for anything the invoice data cannot supply — an Italian Natura code inferred from the VAT scheme, a Romanian county missing from the address — rather than inventing a value that would pass validation and be wrong.

The honest boundary: Nordlet builds and delivers the payload, but the certified national transports (SdI accreditation, KSeF session credentials, ANAF SPV OAuth) are handled by a bridge you configure — an accredited intermediary or your own connector. That is deliberate: those channels require credentials and certification that belong to the taxpayer, not to a software vendor.

FAQ

Is a PDF invoice an electronic invoice?

Not in the legal sense. An e-invoice must be in a structured format that allows automatic processing; a PDF is an image of an invoice. From 1 July 2030 the VAT Directive's definition makes this explicit across the EU.

What is the difference between Peppol and EN 16931?

EN 16931 is the semantic standard defining what an invoice contains. Peppol is a delivery network for exchanging documents, and Peppol BIS Billing 3.0 is its specification built on EN 16931. One is the content, the other is the transport.

Who has to use e-invoicing in the EU?

All public authorities must be able to receive EN 16931 invoices under Directive 2014/55/EU. B2B mandates are national and phasing in — Italy, Poland and Romania already, France and Germany in progress — and intra-EU B2B becomes mandatory from 1 July 2030 under ViDA.

What is a clearance model?

A system where invoices pass through a government platform as they are issued, so the tax authority sees them in real time. Italy's SdI, Poland's KSeF and Romania's e-Factura work this way, in contrast to Peppol's direct network delivery between trading partners.

Do I need my own Peppol access point?

No. Access points are service providers you connect to, and most businesses use someone else's. Nordlet supports configuring your own or using the platform's built-in one.