Invoice outside KSeF despite the seller’s obligation: VAT deduction and evidence

Invoice outside KSeF despite the seller’s obligation: what about VAT deduction?

This article concerns only a buyer who, after 1 April 2026, receives an invoice outside KSeF from a seller required to issue it in the system. We take that obligation as an assumption — we do not determine here whether a particular seller is subject to KSeF. This is not a guide to downloading invoices generally or correcting an incorrect tax identification number (NIP).

The method of issuing the invoice does not itself rule out deduction

According to the Ministry of Finance’s answer to question 1, issuing an invoice outside KSeF, including in breach of the seller’s obligation, does not itself rule out VAT deduction. However, all the conditions identified by the Ministry must still be met:

• the purchased goods or services are used for taxable transactions — deduction is available to that extent;
• the substantive conditions for deduction under Article 86 of the VAT Act are met;
• none of the grounds excluding deduction under Article 88 of the VAT Act apply.

The Ministry gives an invoice documenting a transaction that did not take place as an example of a ground excluding deduction. Its position on the method of issuing an invoice should therefore not be read as unconditional permission to deduct VAT from every document issued outside KSeF.

Due diligence: assess the circumstances of the business relationship

In its answer to question 1, the Ministry also states that a buyer using invoices issued and received outside KSeF should exercise due diligence. The buyer should consider the circumstances of cooperation with the counterparty issuing such invoices on each occasion, particularly where the seller does not comply with VAT rules.

Preserve evidence of the actual transaction

According to the Ministry’s answer to question 5, a taxpayer planning to deduct VAT from an invoice issued outside KSeF should preserve evidence confirming that the transaction actually took place, so that they can demonstrate due diligence in the event of a tax audit. The Ministry gives the following examples:

• payment confirmations;
• acceptance reports;
• email correspondence.

These are examples, not an exhaustive list of mandatory documents for every transaction. Preserving evidence does not guarantee deduction or a favourable audit outcome.

Optional organisation of documentation

As an organisational recommendation, rather than an additional legal obligation, you can collect the invoice and available evidence relating to a particular purchase in one folder and label them so they can easily be linked to the transaction. Such organisation does not replace the conditions for deduction or assessment of the circumstances of the business relationship on each occasion.

Must you ask the seller to issue the invoice in KSeF?

No. In its answer to question 5, the Ministry expressly states that a buyer receiving an invoice outside KSeF is not obliged to ask the seller to issue it in the system.

At the same time, failure to issue an invoice in KSeF despite being required to do so should be a warning sign. The Ministry notes that, from the tax authorities’ perspective, such invoices may increase the risk of scrutiny of the reliability of the entire transaction. The absence of an obligation to ask the seller does not therefore mean that due diligence and evidence of the actual purchase can be disregarded.

The key distinction

In the situation described, the method of issuing the invoice does not itself rule out deduction, but the conditions concerning the use of purchases for taxable transactions, the substantive requirements of Article 86 and the absence of grounds excluding deduction under Article 88 of the VAT Act still apply. The buyer should exercise due diligence, assess the circumstances of the business relationship on each occasion and preserve evidence that the transaction actually took place. The buyer does not have to ask the seller to issue the invoice in KSeF, but bypassing the system despite an obligation remains a warning sign, not a guarantee that the deduction is safe.