KSeF in 2027. What will change for business owners?

1. KSeF will also cover the smallest business owners

If monthly gross sales do not exceed 10,000 PLN, a business owner can use the transitional period for issuing invoices until the end of 2026. But from 1 January 2027 this exemption is due to cease to apply.

This means that even the smallest companies will be covered by the rules on mandatory invoice issuing in KSeF.

It is worth remembering that the obligation to receive invoices through KSeF was introduced earlier. So 2027 will mainly be the moment that closes the system on the issuing side as well, for the smallest entities.

2. From 2027, KSeF-related penalties will start to apply

From 1 January 2027, business owners will have to reckon with the possibility of penalties for certain breaches of KSeF-related obligations.

Penalties may apply, among other things, where a business owner:

• does not issue an invoice in KSeF despite being obliged to
• during a system failure or unavailability, issues a document that does not conform to the required template
• does not submit to KSeF, by the required deadline, an invoice issued in offline mode
• fails to fulfil certain obligations related to submitting a document to the system

The amount of the penalty may depend on the amount of VAT shown on the invoice or on the value of the whole receivable.

This is an important change compared with 2026. The first period of mandatory KSeF is meant to give companies time to adapt their processes, whereas from 2027 using the system correctly will also carry penalties.

3. The KSeF number will also matter in payments

One of the most important changes from 1 January 2027 will be a stronger link between an invoice issued in KSeF and the subsequent payment.

In certain cases, when making a transfer for a structured invoice, it will be necessary to give the KSeF number of that invoice. If a payment covers several documents, a collective identifier generated in KSeF can be used. The change will also apply to some payments made under the split payment mechanism.

In practice this means that KSeF stops being solely a system for issuing invoices.

The whole process will matter more and more:

• invoice → bookkeeping → payment → settlement

Companies should therefore review not only their invoicing software, but also how they make transfers, their accounting automations and their banking integrations.

4. The end of further exceptions and transitional periods

From 1 January 2027, cash registers lose their invoicing function. This means that receipts with a NIP of up to 450 PLN will no longer be simplified invoices, and every B2B sale will require a structured e-invoice issued directly in the National e-Invoicing System (KSeF).

5. KSeF will continue to be developed

Launching the system does not mean the end of its development. The Ministry of Finance is running consultations on further KSeF features and improvements.

One of the directions under analysis is the ability to pass on additional business events related to a specific invoice, and better synchronisation of information between KSeF and business owners’ systems.

It can be assumed that in the coming months KSeF will gradually evolve from a system used mainly for exchanging invoices into a more extensive element of the digital flow of financial documents.

What does KSeF 2027 mean for a business owner?

The biggest change is not limited to the way an invoice is issued.

An invoice appears in the system, then goes to accounting, and is linked to the payment, the bank account and the later settlement.

That is why, before the end of 2026, it is worth checking:

• whether the system you use is properly integrated with KSeF
• who in the organisation has the relevant permissions
• how emergency situations and offline mode are handled
• whether the payment process will handle KSeF numbers correctly
• how authentication of external systems works
• whether the staff responsible for invoices, payments and accounting know the new procedures
• whether data flows automatically between the invoicing system, the bank and accounting