Working with ZUGFeRD invoice

2 Sep 202411 minutes to read

The ZUGFeRD invoice is one of the uniformed data format for electronic invoices based on the ISO standard PDF/A-3, which is specifically designed for long term archiving. The ZUGFeRD invoice contains both human-readable invoice and machine-readable structured invoice data (XML).

Generating ZUGFeRD invoice

The Syncfusion .NET PDF library has support to create PDF document with PDF/A-3b conformance, which allow to add external file to the PDF document as attachment. The ZUGFeRD has two versions, ZugferdVersion 1.0 and ZugferdVersion 2.0. The Zugferd 2.0 is an updated version of Zugferd 1.0.

The ZUGFeRD has five conformance levels,

• Basic: Represents the structured data for simple invoices. Additional information can be included as free text.
• Comfort: Represents the structured data for fully automated invoice processing.
• Extended: Represents the additional structured data for exchanging invoice across different industry segments.
• Minimum: Represents the basic invoice details compatible with the French Standard Factur-X.
• EN16931: Represents the fully compliant with the EU Standard, though it only defines the core elements of an invoice.

NOTE

• The ZUGFeRD conformance levels Minimum and EN16931 are only supported in ZugferdVersion2.0.

The ZUGFeRD invoice document can be created by specifying the conformance level as Pdf_A3B through PdfConformanceLevel Enum when creating the new PDF document and set the ZugferdConformanceLevel property as Basic in ZugferdConformanceLevel Enum.

C# [Cross-platform]

//Create ZUGFeRD invoice PDF document
PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_A3B);

//Set ZUGFeRD conformance level
document.ZugferdConformanceLevel = ZugferdConformanceLevel.Basic;

C# [Windows-specific]

//Create ZUGFeRD invoice PDF document
PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_A3B);

//Set ZUGFeRD conformance level
document.ZugferdConformanceLevel = ZugferdConformanceLevel.Basic;

VB.NET [Windows-specific]

'Create ZUGFeRD invoice PDF document
Dim document As PdfDocument = New PdfDocument(PdfConformanceLevel.Pdf_A3B) 

'Set ZUGFeRD conformance level
document.ZugferdConformanceLevel = ZugferdConformanceLevel.Basic

Using PDF/A-3b conformance, you can create a ZUGFeRD invoice PDF by specifying the ZugferdVersion property as ZugferdVersion2_0 of ZugferdVersion Enum. By default, ZugferdVersion1.0 used.

C# [Cross-platform]

//Create ZUGFeRD invoice PDF document
PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_A3B);

//Specifies ZUGFeRD version            
document.ZugferdVersion = ZugferdVersion.ZugferdVersion2_0;

C# [Windows-specific]

//Create ZUGFeRD invoice PDF document
PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_A3B);

//Specifies ZUGFeRD version 
document.ZugferdVersion = ZugferdVersion.ZugferdVersion2_0;

VB.NET [Windows-specific]

'Create ZUGFeRD invoice PDF document
Dim document As PdfDocument = New PdfDocument(PdfConformanceLevel.Pdf_A3B) 

'Specifies ZUGFeRD version 
document.ZugferdVersion = ZugferdVersion.ZugferdVersion2_0

Adding ZUGFeRD structured data as attachment

The PDF/A-3b conformance supports the external files as attachment to the PDF document using PdfAttachment class.

C# [Cross-platform]

//Creates an attachment
FileStream fontStream = new FileStream("../../Data/ZUGFeRD-invoice.xml", FileMode.Open, FileAccess.Read);
PdfAttachment attachment = new PdfAttachment("ZUGFeRD-invoice.xml",invoiceStream);
attachment.Relationship = PdfAttachmentRelationship.Alternative;
attachment.ModificationDate = DateTime.Now;
attachment.Description = "ZUGFeRD-invoice";
attachment.MimeType = "application/xml";
//Add attachment to PDF document
document.Attachments.Add(attachment);

C# [Windows-specific]

//Creates an attachment
FileStream invoiceStream = new FileStream("../../Data/ZUGFeRD-invoice.xml", FileMode.Open, FileAccess.Read);
PdfAttachment attachment = new PdfAttachment("ZUGFeRD-invoice.xml",invoiceStream);
attachment.Relationship = PdfAttachmentRelationship.Alternative;
attachment.ModificationDate = DateTime.Now;
attachment.Description = "ZUGFeRD-invoice";
attachment.MimeType = "application/xml";
//Add attachment to PDF document
document.Attachments.Add(attachment);

VB.NET [Windows-specific]

'Creates an attachment
Dim invoiceStream As FileStream = New FileStream("../../Data/ZUGFeRD-invoice.xml", FileMode.Open, FileAccess.Read)
Dim attachment As PdfAttachment = New PdfAttachment("ZUGFeRD-invoice.xml", invoiceStream)
attachment.Relationship = PdfAttachmentRelationship.Alternative
attachment.ModificationDate = DateTime.Now
attachment.Description = "ZUGFeRD-invoice"
attachment.MimeType = "application/xml"
//Add attachment to PDF document 
document.Attachments.Add(attachment)

NOTE

*As per the ZUGFeRD standard guidelines, the XML name must be ZUGFeRD-invoice.xml.

Complete code

The complete code to create ZUGFeRD invoice PDF document as follows.

C# [Cross-platform]

//Create ZUGFeRD invoice PDF document
PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_A3B);
//Set ZUGFeRD conformance level 
document.ZugferdConformanceLevel = ZugferdConformanceLevel.Basic;

//Creates an attachment 
FileStream fontStream = new FileStream("../../ Data / ZUGFeRD - invoice.xml", FileMode.Open, FileAccess.Read);
PdfAttachment attachment = new PdfAttachment("ZUGFeRD-invoice.xml",invoiceStream);
attachment.Relationship = PdfAttachmentRelationship.Alternative;
attachment.ModificationDate = DateTime.Now;
attachment.Description = "ZUGFeRD-invoice";
attachment.MimeType = "application/xml";
//Add attachment to PDF document
document.Attachments.Add(attachment);

//Creating the stream object
MemoryStream stream = new MemoryStream();
//Save the document into memory stream
document.Save(stream);
//If the position is not set to '0', then the PDF will be empty
stream.Position = 0;
//Close the document
document.Close(true);
//Defining the ContentType for PDF file
string contentType = "application/pdf";
//Define the file name
string fileName = "Zugferd.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name
return File(stream, contentType, fileName);

C# [Windows-specific]

//Create ZUGFeRD invoice PDF document
PdfDocument document = new PdfDocument(PdfConformanceLevel.Pdf_A3B);
//Set ZUGFeRD conformance level 
document.ZugferdConformanceLevel = ZugferdConformanceLevel.Basic;

//Creates an attachment 
FileStream invoiceStream = new FileStream("../../ Data / ZUGFeRD - invoice.xml", FileMode.Open, FileAccess.Read)
PdfAttachment attachment = new PdfAttachment("ZUGFeRD-invoice.xml",invoiceStream);
attachment.Relationship = PdfAttachmentRelationship.Alternative;
attachment.ModificationDate = DateTime.Now;
attachment.Description = "ZUGFeRD-invoice";
attachment.MimeType = "application/xml";
//Add attachment to PDF document
document.Attachments.Add(attachment);

//Save and close the document
document.Save("Zugferd.pdf");
document.Close(true);

VB.NET [Windows-specific]

'Create ZUGFeRD invoice PDF document
Dim document As PdfDocument = New PdfDocument(PdfConformanceLevel.Pdf_A3B)
'Set ZUGFeRD conformance level 
document.ZugferdConformanceLevel = ZugferdConformanceLevel.Basic

'Creates an attachment
Dim invoiceStream As FileStream = New FileStream("../../ Data / ZUGFeRD - invoice.xml", FileMode.Open, FileAccess.Read)
Dim attachment As PdfAttachment = New PdfAttachment("ZUGFeRD-invoice.xml",invoiceStream)
attachment.Relationship = PdfAttachmentRelationship.Alternative
attachment.ModificationDate = DateTime.Now
attachment.Description = "ZUGFeRD-invoice"
attachment.MimeType = "application/xml"
//Add attachment to PDF document
document.Attachments.Add(attachment)

'Save and close the document
document.Save("Zugferd.pdf")
document.Close(True)

You can download a complete working sample from GitHub.

Extract ZUGFeRD invoice from PDF

You can extract the ZUGFeRD invoice using PdfAttachment class.

C# [Cross-platform]

//Get stream from an existing PDF document. 
FileStream docStream = new FileStream(Path.GetFullPath(@"Data/Input.pdf"), FileMode.Open, FileAccess.Read);

//Load the PDF document. 
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);

//Iterates the attachments.
foreach (PdfAttachment attachment in loadedDocument.Attachments)
{
    //Extracts the ZUGFeRD invoice attachment and saves it to the disk.
    FileStream s = new FileStream("Output/" + attachment.FileName, FileMode.Create, FileAccess.Write);
    s.Write(attachment.Data, 0, attachment.Data.Length);
    s.Dispose();
}

//Close the PDF document. 
loadedDocument.Close(true);

C# [Windows-specific]

//Loads the PDF document
PdfLoadedDocument document = new PdfLoadedDocument("Sample.pdf");

//Iterates the attachments
foreach (PdfAttachment attachment in document.Attachments)
{
//Extracts the ZUGFeRD invoice attachment and saves it to the disk
FileStream s = new FileStream(attachment.FileName, FileMode.Create);
s.Write(attachment.Data, 0, attachment.Data.Length);
s.Dispose();
}

//Saves and closes the document
document.Save("Output.pdf");
document.Close(true);

VB.NET [Windows-specific]

'Loads the PDF document
Dim document As New PdfLoadedDocument("Sample.pdf")

'Iterates the attachments
For Each attachment As PdfAttachment In document.Attachments
'Extracts the attachment and saves it to the disk
Dim s As New FileStream(attachment.FileName, FileMode.Create)
s.Write(attachment.Data, 0, attachment.Data.Length)
s.Dispose()
Next

'Saves and closes the document
document.Save("Output.pdf")
document.Close(True)

You can download a complete working sample from GitHub.

Validating ZUGFeRD invoices using Adobe Acrobat

The ZUGFeRD invoices can be validated as follows:

1. Conformance to the PDF/A-3b standard can be checked with Preflight function in Adobe acrobat.

   • Open the PDF and choose Tools > Print Production > Preflight in the right pane.

   • Select the PDF/A-3b profile and click the Analyze button.

* Check the result

1. Conformance to the ZUGFeRD invoice can be checked as follows:

   • Open the PDF and choose Tools > Print Production > Preflight in the right pane.

   • Select the ZUGFeRD profile and click the Analyze button.

* Check the result