What is a UBL invoice? E-invoicing explained

More and more clients ask for an “e-invoice” or a “UBL file” instead of a PDF. It sounds technical, but the idea is simple: your client’s accounting software wants to read your invoice without anyone retyping the amounts.

UBL in short

UBL stands for Universal Business Language. It is a standard format that stores an invoice as an XML file: a text file in which every detail has its own field. The invoice number sits in the invoice number field, the VAT amount in the VAT field, and so on.

That lets your client’s software read the invoice automatically, check it and queue it for payment. An invoice like that is called an e-invoice.

How it differs from a PDF

A PDF is made to be read by people. A computer only sees an image with text on it and has to guess which amount is the total. A UBL file is made to be read by software: every detail is named unambiguously.

You notice that difference mainly in practice:

Less retyping at your client’s end, so fewer mistakes in amounts and references.
Faster payment, because the invoice lands straight in the payment run instead of in a mailbox.
Fewer rejected invoices, because missing details show up immediately.

So a scan, or a PDF with a QR code, is not an e-invoice. That said, the two are not mutually exclusive: in practice you usually send the PDF and the UBL file together, so a person can read the invoice and the software can process it.

NLCIUS and Peppol: two flavours of the same standard

You will run into two names. Both are based on the same European standard (EN 16931) and the same UBL format, they only impose slightly different requirements:

NLCIUS, also known as SI-UBL 2.0: the Dutch interpretation of the standard. This is what Dutch clients and government bodies typically ask for.
Peppol BIS Billing 3.0: the international variant, used when the invoice travels over the Peppol network or when your client is abroad.

Not sure which one your client wants? Just ask. Choosing costs nothing: it is the same file with a different label on it, and you can produce the other variant of the same invoice in seconds.

When do you need a UBL invoice?

If you supply the Dutch central government, e-invoicing is mandatory. Many municipalities, provinces, hospitals and educational institutions also accept e-invoices only.
Large clients ask for them increasingly often, because their accounts payable process is fully automated.
Across the EU, e-invoicing is becoming the norm for business invoices step by step. Belgium, for instance, requires structured e-invoices between businesses, so if you invoice across the border you may be dealing with it already. See Invoicing a client in Belgium.

For private customers there is no point: a PDF by e-mail is fine there.

What your invoice needs before UBL works

An e-invoice is stricter than a PDF. If a detail is missing, the file is rejected. So make sure you have:

Your company name, address, postcode, city and country.
Your KVK number and your VAT number.
Your IBAN, so the payment can be queued automatically.
The full name and address of your client, plus the country.
With the reverse charge: your client’s VAT number.
An invoice number, invoice date and due date.

Does your client ask for a purchase order number or a reference? Put it on the invoice, because that is what their system looks for. Which details are mandatory in any case is covered in What must a Dutch invoice contain.

How do you send a UBL invoice?

There are two routes:

As an e-mail attachment. You send the PDF and the UBL file to your client, who imports the file into their bookkeeping. This is the simplest way and enough for most freelancers and small businesses.
Over the Peppol network. The invoice then travels straight from your software to your client’s, through an access point. That requires signing up with a Peppol service provider and is mainly worthwhile if you invoice government bodies a lot.

E-invoicing with factuurmaken

In factuurmaken you choose once whether your invoices should follow NLCIUS or Peppol BIS. After that you download the UBL file for any invoice with one click, or have it attached to the invoice e-mail automatically, next to the PDF.

If a detail the e-invoice requires is still missing, you see exactly which field it is before you send. That way you know the invoice will not be rejected at the other end.