zugpferd

https://github.com/alexzeitler/zugpferd

Read, write and convert XRechnung and ZUGFeRD electronic invoices (e-Rechnung) according to EN 16931. Supports UBL 2.1 and UN/CEFACT CII syntaxes with dedicated classes for Invoice, Credit Note, Corrected Invoice, Self-billed Invoice, Partial Invoice and Prepayment Invoice.