KSeF 2026. “The system was designed by someone with no experience.” The IT specialist points out the pros and cons

Ashley Davis01/04/2026

0 42 6 minutes read

From February 1, small and medium-sized companies could, but did not have to, issue invoices in the National e-Invoice System. It was mandatory only for 5,000. large companies. Then Mr. Marek, a micro-entrepreneur operating in the IT industry, issued his first invoice for us at KSeF.

Today, he is testing the government system again, although he uses commercial software integrated with KSeF on a daily basis. Mr. Marek, like almost 346 thousand companies, started issuing invoices to KSeF voluntarily, because in his opinion the system works well, although it causes problems.

— I have the impression that the free tool provided by the Ministry of Finance was designed by a person who has never run even a very small company. They were treated as a bag of invoices, and we have to find our way in this bag, says Mr. Marek. Therefore, in his opinion, it is worth using commercial software, especially since there are free offers on the market.

— However, if someone issues a few invoices a month, the government application is not bad – he adds.

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Login still available

— There have been no major problems with logging in at the moment, except for those at the beginning of February. For example, when I logged in on Monday, after a few minutes of grinding, a strange message appeared about the incorrect system time. But after refreshing, everything started working. Maybe it's the result of the time change or maybe some update. On the night of April 1, I logged in as smoothly as two months ago. We'll see whether the day will be similar to what it was at the beginning of February, says Mr. Marek.

On February 1, on Sunday, while it was a day off from work, KSeF operated, and on Monday, Profil Zaufany went down.

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mf.gov.pl

Zaufany Profile is the only free way to log in to KSeF. Although, as Marcin Łoboda, head of the National Tax Administration, points out, so far users have logged in mainly using certificates (67%) and tokens (27%). This means that so far most people use commercial programs for KSeF. From April 1 this may change. KSeF, designed to accept 120 million invoices a day, will serve nearly 3 million entities. Apart from companies, these include universities, local governments, foundations and associations.

Read also: Experts on the implementation of KSeF. One mistake can be difficult to fix

Issuing an invoice is still tiring

Mr. Marek thinks that issuing invoices in the government application is still not very intuitive. At the beginning, you must indicate one of four types of invoices: basic, advance, settlement or correction.

The system also requires you to choose between a shortened and extended form. The short form hides many advanced fields available in the extended form, e.g. annotations, WZ numbers, transport data.

For people without experience, it is also difficult to know what to mark when you are exempt from VAT.

— This is an option available at the very beginning, but who, apart from an accountant or a tax advisor, understands what “supply of goods or provision of services exempt from tax pursuant to Article 43(1), Article 113(1) and 9 or regulations issued pursuant to Article 82(3) or pursuant to other provisions” means,” says Mr. Darek.

Then you need to provide the invoice number yourself. — It is worth doing it in accordance with the existing system. It is worth knowing that the invoice number assigned by the seller is different from the unique invoice identifier in KSeF – this system generates it automatically only after the document has been sent correctly. Then we enter data regarding the service, price, VAT, our own tax identification number and that of the contractor.

— One thing is certain – before clicking the “issue an invoice” button, it is worth checking everything carefully. The system passes documents with incorrect calculations, a Once an invoice is sent to KSeF, it cannot be corrected or canceled – emphasizes Mr. Marek. And here he sees the biggest problem.

Every mistake needs to be corrected

— Even with a trivial error, an invoice must be corrected, and if the error concerns the Tax Identification Number, even two corrections must be made. – says Mr. Marek. He points out that it is not possible to generate a PDF preview of the invoice throughout the entire process of issuing an invoice. This option is available only after issuing and sending to KSeF – explains Mr. Marek.

Mr. Marek has two contractors with a similar name. And it happened to him, in his old system, that he issued an invoice to the wrong one.

— Before February, I simply canceled it and issued a new invoice with the correct name and tax identification number. Now, if I have already sent an invoice to KSeF with an error, I have to issue a new correct invoice and a corrective invoice – says Mr. Marek. He adds that it is also not possible to cancel an advance invoice sent to KSeF when the customer has canceled the service. – You need to issue a corrective invoice for PLN 0 – says Mr. Marek.

Read also: This is currently the biggest problem in KSeF. One mistake and the entire invoice has to be corrected

There is no currency exchange rate in the free system

Invoices for foreign contractors may also cause problems. — First of all, I see on social media forums that Many people think that if they sell something abroad, they do not have to issue a VAT invoice. However, this is not the case. We issue an invoice to KSeF and send the visualization abroad, says Mr. Marek.

The second problem is the exchange rate. — When I issue an invoice in euro in commercial software, the exchange rate from the last business day appears automatically. This makes the work of me and the accountant easier. There is no such option in the government application. There is a dedicated fieldFa/FaWiersz/KursWaluty for its single row. If there are many items on the invoice, a rate should be assigned to each one, even if it would be the same for each of them. You have to check the course yourself, explains Mr. Marek.

However, there is no legal obligation to include the exchange rate on the invoice. It is important that the VAT amount is given in Polish zloty. Hence, the Ministry of Finance program probably does not have the same facilities as commercial ones.

Coordination is a challenge

According to Mr. Marek, the biggest one the challenge is above all document coordination — especially during the transition period, when some invoices are still sent via the traditional route and others via the new system. – In the case of small companies, accounting has limits on the number of invoices – you have to make sure not to duplicate documents and generate additional costs – says Mr. Marek.

In his opinion, It is important to re-establish the principles of cooperation with the accountant.

— Every day I use commercial software to which the accountant has access, so I have no problems. However, my friend wanted to authorize her accountant to the KSeF account, but she gave up. She didn't have the strength to check what the authorization for an individual to work for a client or a tax representative means? She agreed to send visualizations of e-invoices. You can download invoices collectively from KSeF in XML or PDF format – says Mr. Marek.

However, Mr. Marek understands when someone complains that cooperation with an accounting office may be difficult, especially when there are many invoices, including descriptive ones, or cost invoices are submitted by different people.