What a Peppol invoice must contain: the required fields

A Peppol BIS Billing invoice needs the EN 16931 basics (number, issue date, currency, seller and buyer with postal addresses, totals, and lines with a VAT category) plus Peppol's own rules: an electronic address for both parties and a buyer reference or purchase order reference.

Many of these fields already sit on any well-made invoice. The ones that catch businesses out are the identifiers: the electronic addresses that route the invoice through the network, and the reference the buyer uses to match it on arrival. This guide lists what the specification asks for, so you can gather it before you send an e-invoice.

Two layers of rules

Peppol BIS Billing 3.0 is built on the European standard for e-invoicing, EN 16931. An invoice has to pass both: the EN 16931 business rules (the "BR" rules) and a set of Peppol rules that tighten a few points. If you are new to the standard, what EN 16931 is and why it matters covers the background, and how Peppol works explains the network itself.

The fields every Peppol invoice needs

Group	Required	Rule source
Document	Invoice number, issue date, invoice type code, currency code	EN 16931
Seller	Name, postal address with country code, electronic address	EN 16931 and Peppol
Buyer	Name, postal address with country code, electronic address	EN 16931 and Peppol
Reference	A buyer reference or a purchase order reference	Peppol
Lines	At least one line, each with an identifier, quantity, net amount, item name, net price and VAT category	EN 16931
Totals	Sum of line net amounts, total without VAT, total with VAT, amount due for payment	EN 16931

On top of these, the file carries a specification identifier and a business process identifier. Your e-invoicing software writes both; you never type them.

Electronic addresses: the identifiers that route the invoice

Peppol requires an electronic address for the seller and for the buyer. It is the identifier the network uses to find the right receiver, a bit like an email address for invoices. Each address comes with a scheme identifier that says what kind of number it is.

Depending on the country and the scheme, the electronic address is often a VAT number or a national company registration number. Before you send, check two things:

• Your own address is registered on the network through your access point, with the same scheme and number you put on your invoices. What an access point does explains that registration.
• Each customer's address is stored with the customer, with its scheme. Ask customers for their Peppol identifier when you set them up, rather than guessing from the VAT number.

The buyer reference

Peppol says an invoice must carry a buyer reference or a purchase order reference. Large buyers and public bodies often route incoming invoices by this value, so an invoice without the reference they expect can stall on their side even when it is technically valid.

In practice: ask each customer which reference they want on invoices (a cost center, a contact code, an order number) and store it with the customer, so it is filled in every time.

VAT details

• A VAT category on every line. Each invoice line is categorized with a VAT category code, such as standard rate, zero rate, exempt or reverse charge.
• Country prefixes. VAT identifiers for the seller and the buyer start with the two-letter country code (Greece uses EL).
• Seller VAT identifier. When a line is standard rated, the invoice has to carry the seller's VAT identifier, a tax registration identifier or a tax representative's VAT identifier.
• Currency codes follow the ISO 4217 list of three-letter codes.

Payment details

Payment instructions are not mandatory on every invoice, but when you include them, the rules apply. A payment instruction names its payment means code, and if you give credit transfer details, the payment account (for SEPA transfers, your IBAN) has to be there.

A checklist before you send Peppol invoices

1. Your company's legal name, postal address and country exactly as registered.
2. Your VAT number with its country prefix.
3. Your Peppol electronic address and its scheme, registered through your access point.
4. For each customer: name, postal address with country, VAT number, Peppol electronic address with scheme, and the reference they want on invoices.
5. For each item or service you sell: a clear name and the right VAT category.
6. Your bank account (IBAN) if you put payment details on the invoice.

Keep in mind that some countries add their own national rules on top of Peppol BIS. And a PDF that shows all of these fields is still not an e-invoice: see why a PDF is not an e-invoice. For the structure of the format itself, read Peppol BIS Billing explained.

Frequently asked questions

What is a Peppol endpoint ID?

It is the electronic address of a party on the Peppol network, made up of a scheme identifier and a number. Senders use it to reach the right receiver. Depending on the country, the number is often a VAT number or a company registration number.

Which Peppol fields are most often missing?

In practice, the identifiers and references tend to cause trouble: the buyer's electronic address and its scheme, the buyer reference, and VAT numbers without a country prefix. An invoice missing a required field fails validation and is typically rejected before delivery, so checking these when you set up a customer saves a resend.

Do I need both a buyer reference and a purchase order number?

No. Peppol asks for one of the two. Use the purchase order reference when the buyer gave you an order, and the buyer reference they asked for otherwise. Some buyers expect a specific one, so ask.

Does a Peppol invoice have to include my bank details?

Not always. Payment details are optional, but if you include a credit transfer, the payment account is required. Many businesses include their IBAN so the customer can pay without looking it up.