Generate KSeF-compliant XML for Polish SMEs (The Fast Way)

Following up on my post about Belgium’s PEPPOL fines—today, let’s talk about Poland and KSeF (Aplikacja Podatnika KSeF).

Polish micro and small businesses are currently navigating a massive shift. KSeF is becoming mandatory, and with it, the rules of the game have changed. Under the new mandate, every invoice must:

- Be submitted directly to the national KSeF system.

- Use the FA(3) XML format (the official logical structure).

- Pass validation before it is considered legally valid.

The bottom line: If you only send a PDF, it is no longer a legal invoice in Poland.

If you’re struggling with KSeF XML generation, I’m happy to share the tool I built or hear your feedback. I’ve also included links to the official government portals at the bottom of the page