The KSeF system is a government system. Therefore, the Polish Ministry of Finance provides taxpayers with free tools for using the KSeF system.
Companies that are VAT payers in Poland must first register a natural person with the tax office who will use the KSeF system on their behalf.
Registration is done using the ZAW-FA form, which must be submitted to the tax office in paper form.
A test version of the KSeF system is available at: https://ksef.mf.gov.pl/web/login
E-invoicing (#KSeF) in Poland from 2026 – System Access