First KSeF Invoice Before 1 January 2027: A Micro-Seller Checklist

If your monthly invoiced sales stay at or below 10,000 PLN brutto, you may still issue paper or PDF invoices outside KSeF. This concession ends on 31 December 2026. From 1 January 2027, every VAT payer, regardless of size, must issue through KSeF.

The concession is irreversible. Once you issue a single invoice that pushes your monthly sales above 10,000 PLN brutto, the KSeF obligation attaches from that invoice and never reverts. You do not get the concession back if your sales drop the next month.

A second relief also ends 31 December 2026: receipts with a buyer NIP up to 450 PLN count as simplified invoices outside KSeF. From January 2027, they no longer qualify.

Who Needs to Prepare

If you are a micro-seller, a B2C business that occasionally issues B2B invoices, or a freelancer whose monthly invoicing hovers near 10,000 PLN, you need to prepare for KSeF before January 2027. The four obligations converging on that date are:

1. KSeF issuance mandatory for all. No more paper. No more PDF. Every B2B invoice goes through KSeF.
2. Penalties activate. Up to 100% of the VAT shown on an invoice issued outside KSeF (art. 106ni). The 2026 education period, during which penalties are not applied, ends.
3. KSeF number in payment titles. Art. 108g requires the KSeF number in bank transfer titles between active VAT payers.
4. Receipts with NIP stop counting as invoices. The 450 PLN simplified invoice relief ends.

Preparation Checklist

Before October 2026

• Choose your KSeF authentication method. Token or qualified certificate. Do not rely on Profil Zaufany as your primary method. The launch failure on 2-3 February 2026 was Profil Zaufany under 8x normal traffic. Token-based auth is more reliable.
• Select invoicing software. If you do not already use invoicing software that supports KSeF 2.0, choose one. All four Polish SMB leaders (Fakturownia, iFirma, wFirma, inFakt) ship KSeF support. Or use Plandesk, which adds pre-send validation.
• Set up your KSeF account. Register at ksef.podatki.gov.pl. Authenticate with your NIP. Generate a token.
• Test with a dummy invoice. Issue a test invoice through your chosen software to verify the end-to-end flow: draft, validate, submit, receive KSeF number, download UPO.

October to December 2026

• Monitor your monthly invoiced sales. If you approach 10,000 PLN brutto in any month, the obligation may attach before January. Track your running total.
• Migrate active clients to KSeF delivery. Stop emailing PDFs. Inform B2B clients that invoices will arrive through KSeF from January (or earlier if you cross the threshold).
• Train your staff. Anyone who issues invoices needs to know the KSeF workflow: draft, validate, submit, check status, archive UPO.
• Set up offline mode. Configure your invoicing tool for offline24 mode. Test it. If KSeF is unavailable when you need to issue an invoice, offline24 lets you issue locally and submit by the next working day. The P_1 issue date is preserved.
• Review your invoice numbering. KSeF does not impose a numbering scheme, but your existing scheme must be unique per entity per year. If you have multiple entities, each needs its own sequence.

January 2027

• Issue every B2B invoice through KSeF. No exceptions. No paper. No PDF-only.
• Include the KSeF number in payment titles. For bank transfers between active VAT payers.
• Archive every UPO. The UPO is your proof of delivery. Store it with the invoice record.
• Expect the penalty regime. A single invoice issued outside KSeF can cost up to 100% of its VAT amount. The education period is over.

The 10,000 PLN Threshold: How It Works

The threshold is monthly and cumulative within a month. It is measured as brutto sales (including VAT). If your January sales are 8,000 PLN, you are under the threshold. If your February sales are 12,000 PLN, the KSeF obligation attaches from the first invoice that pushes February's total above 10,000 PLN. Every invoice from that point forward goes through KSeF, even if March drops back to 5,000 PLN.

The threshold is per entity, not per person. If you run a JDG and a spółka, each has its own 10,000 PLN threshold. But both lose the concession on 31 December 2026 regardless.

This material is information of a general nature and does not constitute legal or tax advice. For a specific situation, verify the current rules or consult a qualified adviser.