National e-Invoice System (KSeF) is one of the permitted forms of documenting transactions, alongside paper invoices and electronic invoices currently in economic circulation. The implementation of KSeF in a company is mandatory for:
- large enterprises from 1.02.2026 – in the event that the gross sales value (including the tax amount) exceeded PLN 200 million in 2024,
- other enterprises from 1.04.2026.
A structured invoice is an invoice issued by taxpayers through an information and communication system (KSeF), marked with an identification number assigned in that system.
Receiving structured invoices using KSeF will require the acceptance of the retail recipient or foreign contractor. In the event that the recipient does not agree to such a form of document, the issuer has the right to issue a structured invoice in the system, but its delivery to the recipient should take place in a manner agreed upon with them.
- 237.204.182 – access to the demo environment
- 237.204.187 – access to the production environment
Additionally, port 443 must be unblocked.
Logging in to KSeF is possible using:
- Certificate – it is possible to specify a qualified certificate or a KSeF certificate. More information on this topic can be found in the article Authentication using a KSeF certificate.
- Token – possible only until 31.12.2026. After this date, the use of the token will be disabled.