Poland KSeF: Mandatory E-Invoicing Now Live in Phases (Feb / Apr 2026)
Poland's National e-Invoicing System (KSeF) finally went mandatory in 2026 after multiple postponements. Here's the phased timeline, the centralised clearance model, and what foreign suppliers should know.
After two postponements and a high-profile rebuilding effort triggered by performance issues in 2024, Poland's Krajowy System e-Faktur (KSeF) — the National e-Invoicing System — has gone mandatory in two phased waves in 2026.
Poland's model is a centralised clearance model similar to Italy's SdI: every invoice is sent to KSeF, validated, stamped with a unique KSeF reference, and only then considered legally issued.
The 2026 mandatory timeline
- 1 February 2026 — mandatory KSeF for taxpayers with the previous year's sales value (including tax) above PLN 200 million.
- 1 April 2026 — mandatory KSeF for all other VAT-registered taxpayers (active and exempt).
- 1 January 2027 — mandatory KSeF for the smallest taxpayers issuing only B2C-style simplified invoices via cash registers.
How KSeF works (centralised clearance)
- The supplier's accounting software submits the invoice in the FA(3) XML format to the KSeF API.
- KSeF validates the structure, stamps the document with a unique KSeF reference number, and issues an Acknowledgement of Receipt (UPO).
- The legally binding issue date is the moment KSeF assigns the reference number — not when the supplier hits send.
- The buyer retrieves the invoice from KSeF; outside-KSeF distribution (PDF, email) becomes redundant for in-scope transactions.
B2C and cross-border
B2C invoices are not in KSeF's mandatory scope, but optional issuance through KSeF is permitted (and brings benefits like accelerated VAT refunds — 40 days instead of 60).
Cross-border invoices issued by Polish suppliers to non-Polish customers are also not mandatorily in KSeF. However, Poland aligns with the EU's ViDA roadmap, meaning cross-border invoicing will join the mandate by 1 July 2030.
What foreign suppliers should do
If you sell into Poland from abroad, you generally do not issue invoices into KSeF. But Polish buyers increasingly expect KSeF-style structured input, and large Polish ERP-driven buyers may insist on PEPPOL or KSeF-compatible XML even from foreign suppliers as part of their procurement chain.
Practical advice: your invoicing tool should support EN 16931 / PEPPOL BIS — Hisabi does — so structured XML can be produced for Polish counterparties on request.
Sources
- Polish Ministry of Finance — KSeF programme announcements 2024–2025.
- Act of 16 June 2023 amending the Polish VAT Act (Journal of Laws 2023 item 1598), as further amended in 2024 and 2025 with revised effective dates.
- KSeF technical documentation — FA(3) XML schema published by the Polish National Revenue Administration.