The Krajowy System e-Faktur (KSeF) becomes mandatory for large companies in February 2026 and for all other businesses in April 2026, with all companies required to have the capability to receive invoices through the system from February 2026. Businesses must prepare their IT systems for KSeF integration, as testing for the KSeF 2.0 API is set to begin in September 2025, followed by a test application’s availability in November 2025.
Source: crido.pl
Note that this post was (partially) written with the help of AI. It is always useful to review the original source material, and where needed to obtain (local) advice from a specialist.
