UBL, XML, PDF: what is the difference for your invoices?
Updated July 2026
A PDF is an image of an invoice: a human reads it, but software has to re-enter everything. XML is a structured format, readable by a machine. UBL is a standardised type of XML for business documents — the format of Peppol invoices. For B2B in Belgium in 2026, you need UBL (via Peppol), not a plain PDF.
The PDF: readable, but "mute" to software
The PDF is what everyone uses today: a nice layout, your logo, a document you open and read at a glance. The problem? To a computer, it's an image. Your client's accounting software doesn't "understand" the figures: someone has to re-enter the amount, the VAT and the due date by hand.
The result: wasted time and copying errors. The PDF is perfect for the human eye, not for automation.
XML: the same information, but structured
XML puts the information into labels the machine reads directly. Instead of an image, you have named data: "here is the net amount", "here is the VAT rate", "here is the due date".
A simplified snippet looks like this: <NetAmount>1000</NetAmount>. It's not meant to be read by a human, but software understands it instantly — with no re-entry.
UBL: a standardised XML for business
There are a thousand ways to structure XML. For all software to understand each other, common rules are needed: that is UBL (Universal Business Language). It's an XML standardised specifically for business documents — invoices, orders, credit notes.
That is exactly what Peppol uses: the Peppol BIS format builds on UBL. In other words, a Peppol invoice is a UBL file sent over the Peppol network.
The comparison at a glance
| UBL (XML) | ||
|---|---|---|
| Readable by a human | Yes | Not directly |
| Readable by software | No (re-entry needed) | Yes, automatically |
| Peppol B2B 2026 compliant | No | Yes |
| Risk of entry error | High | Low |
Does the PDF disappear entirely?
No. The PDF stays useful as a readable version — for your archive, a preview, or a client who wants to "see" their invoice. But for a B2B transaction in 2026, the invoice that counts is the UBL sent via Peppol.
In practice, good software generates both: the UBL that goes to the client, and a readable PDF for you. You don't have to choose.
What do I actually have to do?
- Nothing technical: you never create a UBL or XML file by hand
- Peppol-compatible invoicing software generates the UBL and sends it for you
- You keep seeing a readable invoice (PDF); the client receives the structured UBL
- You don't need to know how to read XML
- You don't have to install a separate technical tool
Quick glossary
- PDF: a document-image, readable by humans, not usable automatically
- XML: a structured data format, readable by machines
- UBL: a standardised XML for business documents (the format of Peppol invoices)
- Peppol BIS: the precise rules of the Peppol invoice, based on UBL
- Access point: the service through which your software sends the invoice on the Peppol network
Frequently asked questions
Is a PDF invoice still valid?+
For an individual (B2C), yes. For a business-to-business (B2B) transaction in Belgium from 2026, the invoice must be structured (UBL via Peppol) — a PDF alone is no longer enough.
Are UBL and XML the same thing?+
UBL is a type of XML: an XML that follows standardised rules for business documents. All UBL is XML, but not all XML is UBL.
Do I have to handle UBL files myself?+
No. Compatible invoicing software generates and sends the UBL automatically. You only see a readable invoice and a "send" button.
Can I still keep a PDF for my records?+
Yes. Most software also produces a readable PDF version alongside the UBL, handy for your archive and previews.
Read also
What is Peppol? The simple guideHow to send a Peppol invoice (step by step)B2B e-invoicing 2026: am I concerned?Compliant UBL invoices, without thinking about it
With Afrimo, every invoice is generated in UBL/Peppol and as a readable PDF, with the right VAT — in FR/NL/EN. You click "send", the format is handled.
This article is informational and does not constitute legal or tax advice. Terms may change: check your situation with the tax authorities or your accountant.