Validate Poland's e-invoices offline against the official XSD, then make your validator fail on purpose

Since 2026, invoices between Polish businesses are XML documents. They go to the national e-invoicing system, KSeF, in a schema called FA(3). The last exemptions end on 1 January 2027. Once KSeF accepts an invoice, you cannot edit it or withdraw it. The only fix is a correcting invoice, filed after the fact. So when I changed the XML builder to... Weiterlesen