Quick start
KSeF Kit files your Stripe invoices to KSeF — automatically. Setup is three steps; your first test invoice takes a minute.
1. Install the Stripe App
Install KSeF Kit from the Stripe App Marketplace on your Stripe account. This is the cloud edition — you host nothing. Installing provisions an account and an active Stripe link; from then on every finalized invoice reaches us by webhook.
Prefer to run it yourself? See Self-hosting.
2. Onboarding (3 steps)
After signing in, a wizard walks you through three steps. The next incomplete step opens itself.
- Stripe — the link is created when you install the app.
- Company profile — enter your NIP. We validate the checksum and pull your name and address from the registry (MF Biała lista / GUS). These become the seller details on the invoice.
- Connect KSeF — the TEST environment first (preselected), then paste your token. Details: Connecting KSeF.
You can skip the KSeF step — invoices then wait safely in the queue and are not filed until you connect.
3. First test invoice
Once KSeF is connected we trigger the "aha" moment: we file a sample invoice through the normal pipeline against TEST. When the UPO comes back, you know it works — before your first real invoice arrives.
The UPO (official receipt) is the signed document KSeF returns once it accepts an invoice — together with the KSeF number it assigns. It's your legal proof the invoice was filed. We keep it with every accepted invoice.
All of this happens in the TEST environment (a sandbox) — with no legal effect. Test freely. See Data & security.
Next
- Switch to PROD once TEST works — deliberately, with a confirmation. See Connecting KSeF.
- Understand the flow: How filing works.
- What we store and how: Data & security.
- Limits and plans: Plans & billing.
KSeF is mandatory from 1 January 2027. Worth being ready early — the in-app readiness checklist walks you through it.