What is a PDF invoice exactly?
PDF is a format of visual presentation. It captures an image of your invoice — like a photo — so that it's readable by anyone. It's perfect for the human eye, but disastrous for machines.
When your client receives a PDF, their accounting department must manually re-enter the data (amount, date, VAT number, IBAN) or use an OCR — which makes mistakes. Each invoice = risk of entry error.
What is a UBL invoice?
UBL (Universal Business Language) is a structured XML format — a text file that machines read perfectly. Each piece of information is in a defined field:
<cbc:Amount currencyID="EUR">1210.00</cbc:Amount>
<cbc:TaxAmount currencyID="EUR">210.00</cbc:TaxAmount>Your client's accounting software reads this file and automatically imports all the data. Zero manual entry. Zero errors.
Side-by-side comparison
| Criterion | UBL XML | |
|---|---|---|
| Readable by humans | Yes | No (raw XML code) |
| Readable by machines | Difficult (OCR) | Yes, natively |
| Manual entry on client side | Often necessary | Never |
| Risk of error | High | Virtually none |
| Peppol compatible | No | Yes |
| Mandatory B2B Belgium 2026 | No | Yes |
| File size | Large (images) | Small (text) |
Do I have to choose between the two?
No. In practice, good invoicing software generates both simultaneously:
- A PDF that you (and your client) can read and archive
- A UBL XML that travels via Peppol and integrates into your client's accounting
Ledgerly does exactly that: when you send an invoice via Peppol, the PDF is automatically attached to the Peppol message. Your client receives both.
Does the PDF remain valid after 2026?
For B2B invoices (between VAT-registered Belgian companies): no, the PDF alone will no longer be compliant from January 1, 2026. It must be mandatorily accompanied by a UBL transmitted via Peppol.
For invoices to individuals: the PDF remains perfectly valid.
What this changes for you concretely
If you use Ledgerly: nothing. You continue creating your invoices as before. It's the software that generates the UBL and sends it via Peppol automatically. You don't need to know the UBL format.
If you use Word or Excel for your invoices: you will need to migrate to Peppol-compatible software before January 2026.