In addition to PDF invoices, you can also submit UBL files (XML e-invoices) by email to eConnect. A valid UBL invoice is processed directly without OCR recognition, which is faster and more reliable than PDF conversion. This article explains how it works and what happens when the XML is not valid.

When you submit a UBL invoice by email, the platform validates the file directly against the supported standards. The following UBL formats are recognized:

• SI-UBL 2.0 (NLCIUS, the Dutch standard)
• Peppol BIS Billing 3.0 (the European Peppol standard)

Is the XML valid? Then the invoice is processed and delivered immediately, without the need for OCR recognition. This means faster processing and higher reliability, since no interpretation of visual elements is involved.

If the XML file is not valid (for example due to missing required fields or a deviating structure), the platform automatically switches to a fallback. How that fallback works depends on the situation:

• UBL with accompanying PDF: if an invalid XML is accompanied by a PDF invoice in the same email, the PDF is processed via OCR recognition.
• UBL without PDF: if no PDF has been included, the invoice cannot be processed and you will receive an error message.

Tip: want to check in advance whether your UBL file is valid? Use the eConnect Document Validator, a free online tool that lets you validate any UBL file.

ZUGFeRD (Germany) and Factur-X (France) are hybrid invoice formats: a PDF containing an embedded XML in CII format. For these invoices, the platform first attempts to extract and process the embedded XML.

If the embedded XML is not valid, the system falls back to OCR processing of the PDF component. A ZUGFeRD invoice that passes external validators but is still processed as a PDF by eConnect may indicate a difference in the validation rules for the embedded XML.

The older SimpleInvoicing formats (SI 1.1 and SI 1.2) have not been permitted on the Peppol network since 2024. When submitted by email, eConnect can still transform these formats into a valid NLCIUS invoice in many cases, provided all essential data is present. If data is missing, validation may fail.

The recommendation is to upgrade to SI-UBL 2.0 (NLCIUS) or Peppol BIS Billing 3.0 for reliable processing.

eConnect has a feature that automatically repairs known errors in UBL files through an XSL transformation. Non-essential missing fields are populated with default values, allowing the invoice to be processed after all. This feature is continuously improved based on patterns encountered in practice.

It's useful to understand the distinction between conversion and transformation:

• Conversion: a PDF invoice is converted into an e-invoice (XML). This requires OCR recognition and always involves an interpretation step.
• Transformation: an e-invoice in one XML format is converted into another XML format. This is more reliable because the source data is already structured.

eConnect supports automatic transformation between more than 20 XML standards, including industry-specific formats such as DICO, SETU, SEEF and XRechnung.

Would you rather receive invoices directly via Peppol instead of by email? This is possible if your organization is registered on the Peppol network.

• Submitting purchase invoices by email
• Requirements for submitting invoices
• How does Scan & Recognise (IDR/OCR) work?
• Error messages when submitting by email