Mustang, a Factur-X/ZUGFeRD solution

Mustangproject (download) is a open source library and command line tool for FacturX/ZUGFeRD, a PDF-based format for electronic invoices. You can support electronic invoices in your own java software with the library or extract, add or validate ZUGFeRD metadata using the command line tool. Mustangproject 2.5.6 was released on 22.09.2022 and supports ZUGFeRD 2.2.0, ZUGFeRD 1, Factur-X 1 as well as UN/CEFACT CII XRechnung.

News archive


  • Convert PDF/A1 to PDF/A3
  • Read and write ZUGFeRD 1 and ZUGFeRD 2
  • Embeddable java library based on PDFbox
  • Permissive license (APL2, free for use in commercial and noncommercial applications)
  • The Mustangproject library
    • supports Maven
    • can be embedded in your Java software
  • Command line tool
    • Runs on Linux, Mac OS and Windows
    • Add ZUGFeRD XML to PDF
    • Extract ZUGFeRD XML from PDF
    • Convert CII to UBL
    • Migrate ZUGFeRD 1 to 2 (experimental)
    • Convert PDF/A-1 to PDF/A-3
    • Find out how many PDFs are ZUGFeRD
Screenshot of Acrobat Adobe PDF Reader showing a ZUGFeRD invoice with open file attachments tab
At the right you see a sample
PDF containing Factur-X/ZUGFeRD metadata generated with the Mustang library. If you open it in Adobe Acrobat Reader just click on the paperclip symbol to see the embedded ZUGFeRD XML structure. It has been created using the invoice class. Which you can also use to create a XRechnung.