Peppol does not accept arbitrary UBL, XML or proprietary documents. A message can be exchanged only when its exact document type and process identifiers are registered and the recipient has published support for that capability.

Most business exchanges use an applicable Peppol BIS or Peppol PINT specification. A service provider may convert another source format into a supported Peppol document, but the conversion must preserve the required business meaning and the resulting document must pass the applicable validation rules.

Using Peppol can support regulatory compliance, but network transmission alone does not make a document legally compliant. The sender, receiver and service provider must also meet the rules that apply to the transaction and jurisdiction.