KSeF - How to Prepare a Multi-Channel Company

KSeF is a central system through which structured invoices pass in a uniform format. Instead of emailing a PDF, you issue an invoice into the system and the recipient retrieves it there. The key point for you: every system that issues invoices today must be able to pass them to KSeF. A fuller explanation of the concept is in our glossary: /slownik/ksef.

A single-channel company issues invoices in one program - one connection to KSeF and done. A multi-channel company issues invoices in several places at once: in the accounting system, sometimes in a marketplace tool, sometimes manually for a large B2B client. Each source must reach KSeF consistently, without duplicates and without invoices that slip past the system.

Sit down and list every place where an invoice or a receipt-plus-invoice is created today. Marketplace, own shop, accounting system, manual invoices, corrections, advances. For each source note who issues it and in which system. This list is usually longer than the board assumed - and it defines the scope of the KSeF project.

The healthiest setup is to route all invoices through one system that talks to KSeF - usually the accounting system. Orders from various channels flow into it, and it issues and forwards the invoice to KSeF. For many Polish companies that point is Comarch Optima; we described how to connect channels with Optima separately: /integracje/comarch-optima. You then avoid the situation where three systems send to KSeF and nobody knows which is the source of truth.

Do not test only an ordinary domestic invoice. Check the cases that break systems: corrections, advance invoices, foreign sales, marketplace returns, a customer without a tax ID. These generate validation errors on go-live day. Better to find them in a test environment than on real sales.

Permissions in KSeF, certificates and who technically authorises sending can take more time than the integration itself. Arrange access and roles early, test the full loop on sample documents, and only then switch production. A multi-channel company that starts a week before the deadline does it in panic - and an invoice that does not reach KSeF is, formally, an invoice that does not exist.