Convert PDF to UBL using REST-API

Convert a PDF invoice into a UBL 2.1 XML document, fully compliant with the EN 16931 standard and ready for transmission over the Peppol network. UBL (Universal Business Language) is the OASIS XML standard used by Peppol BIS Billing 3.0 and is the mandated e-invoicing syntax in Norway, Denmark, Sweden, Singapore, Australia, New Zealand, and across the broader Peppol ecosystem.

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POST https://api.invoicexml.com/v1/transform/to/ubl

Request

Parameter	Type	Description
file *	binary	The PDF invoice file to convert.
strict	boolean	Defaults to `false`. When `true`, treat validation warnings as errors — the request is rejected if any warning is raised, not just errors.
version	string	Standard version (e.g. `2.3.2`). Defaults to the latest supported version.
profile	string	Compliance profile. Values: `minimum`, `basicwl`, `basic`, `en16931`, `extended`. Defaults to `en16931`.
syntax	string	XML syntax: `cii` (Cross Industry Invoice) or `ubl` (Universal Business Language). Defaults to `cii`.

Content-Type: multipart/form-data

Headers

Header	Value
Authorization *	Bearer YOUR_API_KEY
Content-Type	multipart/form-data

Response

200 Returns the UBL 2.1 XML document.

Content-Type: application/xml

Code Example

curl -X POST https://api.invoicexml.com/v1/transform/to/ubl \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "[email protected]" \
  -F "version=2.3.2" \
  -F "profile=extended" \
  -F "syntax=cii"

Frequently Asked Questions

What is UBL 2.1?

UBL (Universal Business Language) 2.1 is an OASIS XML standard for electronic business documents. It is one of the two official syntaxes of the European EN 16931 e-invoicing standard and is the native XML format of the Peppol network.

Is the output Peppol BIS Billing 3.0 compliant?

Yes. The generated UBL 2.1 XML conforms to the Peppol BIS Billing 3.0 specification. It is validated against EN 16931 business rules and Peppol-specific constraints before delivery.

Which countries require Peppol UBL invoicing?

Peppol UBL invoicing is mandatory for public sector B2G in Norway, Denmark, Sweden, Finland, Singapore, Australia, and New Zealand. The Netherlands, Belgium, and Italy are rapidly expanding Peppol adoption to B2B transactions.

How does UBL differ from CII?

Both UBL and CII are valid EN 16931 syntaxes. UBL 2.1 is the format of Peppol BIS Billing 3.0 — use it when transmitting over the Peppol network. CII is used by ZUGFeRD and Factur-X hybrid PDFs, which are more common in Germany and France.

Can I submit the output directly to a Peppol access point?

Yes. The generated UBL 2.1 document is a standards-compliant XML file ready for submission to any Peppol-certified access point. You may also pass it to your ERP or accounting system that supports UBL import.