Discover the most common KSeF implementation challenges in 2026: XML validation errors, invoice visibility problems, contractor data quality, and emergency situations. Learn how to solve them effectively.
Poland's mandatory e-invoicing system covers virtually all VAT taxpayers from April 2026. Find out who is exempt and what the penalties are.
No. KSeF does not accept a PDF as a valid invoice. You submit FA(3) XML to the system; a PDF serves only as a visual representation or a source for conversion.
Self-billing reverses the roles — the buyer issues the invoice on behalf of the seller. In the era of mandatory KSeF, this requires proper permissions and a tool for mass document submission. Find out how it works and how ksefgpt solves it.
Retyping one invoice seems trivial — the problem starts when there are a hundred per month. From February 2026 KSeF becomes mandatory. A guide to PDF-to-XML conversion, validation pitfalls, and choosing the right tools.
We explain the differences between tokens and certificates, show you how to generate them, and when to use each.