KSeF e-invoicing

What it does

In Poland, every VAT invoice issued in POSolid is sent automatically to KSeF, the National e-Invoicing System (Krajowy System e-Faktur). POSolid turns the invoice into the official e-invoice (FA(3)), sends it in the background, and keeps trying until KSeF accepts it and gives it a KSeF number. The same connection also brings your suppliers' invoices in from KSeF.

Getting started

1. Set up invoicing as in Invoicing setup — with a valid NIP and PLN as the currency.
2. Connect KSeF: choose the environment and save the venue's KSeF certificate. See KSeF connection setup.
3. Issue invoices as usual (see Issuing invoices). Each one goes to KSeF on its own; follow it in KSeF statuses and Needs attention.
4. Receive suppliers' e-invoices into stock — see Supplier invoices from KSeF.

Key things to know

• Three environments. A new venue starts on Test, where invoices have no legal effect. Demo is KSeF's pre-production environment (your real NIP and certificate, fictitious invoice data). Only after you switch to Production are invoices real.
• Logins: a KSeF token works until 31 December 2026. From 1 January 2027 KSeF accepts only a certificate, so set one up before then.
• The receipt's NIP rule. If the receipt (paragon) was printed, a Polish company invoice for that order must use the NIP printed on it. That's why the payment dialog asks for the NIP before payment when you choose Issue an invoice after payment. Private persons and foreign buyers aren't affected.
• Invoice for a receipt. A sale already printed on the fiscal printer is marked on the invoice as issued for a receipt, so the accountant leaves it out of the sales register, which already has the till's report.
• The PDF becomes the invoice when KSeF accepts it. It then carries the KSeF number and a QR code anyone can scan to check it in KSeF.
• Nothing reaches KSeF twice. If it's unclear whether KSeF received an invoice, POSolid checks with KSeF before sending it again.
• Test and Demo invoices don't touch stock. An invoice without an order issued into a test environment takes nothing out of stock and leaves a supply plan open for the real invoice.
• Who can do what: the KSeF environment and login need the Manage invoices permission.

FAQ

Q: Are invoices issued on Test legally binding?
A: No. Test and Demo invoices go to KSeF's test environments and have no legal effect. Only invoices issued after you switch to Production are real invoices.

Q: The form says the NIP doesn't match the receipt. What now?
A: The receipt was printed with a different NIP or none. A Polish company invoice must carry the NIP from the receipt; otherwise issue it to a private person, or ask your accountant.

Q: Can I invoice a delivery-platform order?
A: Not at the moment. The platform may be the one invoicing that customer; this is being confirmed.

Q: Is my venue in KSeF if it's outside Poland?
A: No. KSeF applies only to venues whose organization country is Poland; elsewhere invoices are issued and kept in POSolid only.