KSeF for a sp. z o.o.: duties in 2026 and from 2027

A sp. z o.o. must issue invoices in KSeF (Krajowy System e-Faktur, the national e-invoicing system) from 1 April 2026, or from 1 February 2026 if its 2024 sales exceeded 200 million zł including VAT. Until 31 December 2026 it may still issue invoices outside KSeF, but only while the gross total of such invoices in a month is no more than 10,000 zł; from 1 January 2027 KSeF applies to every company.

Legal status as of 9 October 2026.

Receiving invoices through KSeF applies to all businesses from 1 February 2026, including those that still use the 10,000 zł limit for their own sales invoices.

KSeF deadlines for a sp. z o.o.

The legal form does not matter. The duty covers both active VAT payers (czynni podatnicy VAT) and VAT-exempt companies that issue invoices to other businesses.

The 10,000 zł limit until the end of 2026

Until 31 December 2026 a company may issue paper or electronic invoices (a PDF, for example) outside KSeF if the total sales including VAT documented by such invoices in a given month is no more than 10,000 zł (art. 145m ust. 1 of the VAT Act).

How to count the limit, according to the Ministry of Finance:

1. Count only invoices that would normally have to go through KSeF. Do not count invoices to consumers, cash register invoices or receipts with the buyer's NIP up to 450 zł.
2. Assign each invoice to the month in which it is issued, not the month of the sale.
3. The invoice that takes you over 10,000 zł must already go through KSeF. From that invoice on, you lose the right to invoice outside the system until the end of 2026 (art. 145m ust. 2 of the VAT Act).

Example: in October a company issued invoices of 6,000 zł and 3,000 zł gross outside KSeF. The next invoice of 2,500 zł brings the total to 11,500 zł, so that invoice and every later one goes through KSeF. Lower sales in November change nothing.

Receiving invoices

A structured invoice (faktura ustrukturyzowana) is issued and received through KSeF (art. 106gb ust. 1 of the VAT Act). It counts as received on the day KSeF assigns it a number (art. 106na ust. 3 of the VAT Act). The buyer does not accept the invoice and the system sends no notifications, so someone in the company, or the accounting software, must check for new purchase invoices regularly.

Invoices from foreign suppliers do not go into KSeF. The company receives them as before.

The KSeF number on invoices and in payments

KSeF assigns the number once it accepts the file. You need it in three situations:

• Correcting invoice (faktura korygująca): it must show the KSeF number of the invoice it corrects (art. 106j ust. 2 pkt 2a of the VAT Act).
• Invoice handed over outside KSeF, for example as a PDF for a foreign client: it must carry a QR code that links to the invoice in the system (art. 106gb ust. 5 of the VAT Act).
• Bank transfer for an invoice: for payments made from 1 January 2027, an active VAT payer paying another active VAT payer by transfer must put the invoice's KSeF number, or a collective identifier from KSeF, in the transfer title (art. 108g ust. 1 of the VAT Act). The payee's status is checked in the VAT taxpayer register (the "white list") on the payment date (art. 108g ust. 3). From the same date the KSeF number also goes into split payment (MPP) transfer messages (art. 108a of the VAT Act as applied from 2027).

Logging in: signature, seal, token and KSeF certificate

KSeF has no username and password. You log in with Profil Zaufany (the government trusted profile), a qualified signature, a qualified seal, a token or a KSeF certificate. A PESEL number alone is not enough.

• Token: a person with permissions generates it in Aplikacja Podatnika KSeF (the Ministry's KSeF taxpayer app) and enters it in the accounting software. The software then works within that person's permissions. The Ministry of Finance has decided that tokens stay in KSeF 2.0 indefinitely, not only until the end of 2026; the regulation on using KSeF is to be amended accordingly.
• KSeF certificate: there are two types. Type 1 is for logging in, type 2 for marking offline invoices with the second QR code. A certificate is valid for at most 2 years.
• Company certificate: issued after authentication with a qualified seal containing the company's NIP. The company may pass it to employees and is itself responsible for controlling and revoking it. A certificate issued to a natural person must not be shared.

Who in the company gets permissions

The route depends on whether the company has a qualified seal with its NIP.

1. A company with a qualified seal logs in with it and uses the default owner permissions (uprawnienia właścicielskie), with no filing at the tax office.
2. A company without a seal files a ZAW-FA notice with the tax office, signed by a person who represents the company. It names one natural person, for example a board member or the finance director. That person does not have to be a board member.
3. The person named in ZAW-FA grants further permissions electronically in KSeF: to employees, a bookkeeper or an accounting firm. No further ZAW-FA is needed.
4. If the person named in ZAW-FA leaves and nobody else has full permissions, the company files a new ZAW-FA.

Who may use KSeF is set out in art. 106nb of the VAT Act. The types of permissions and the ZAW-FA form are set out in the Regulation of the Minister of Finance and Economy of 12 December 2025 on using KSeF (Dz.U. 2025 poz. 1815).

Offline modes

You can issue an invoice outside the system, but in the FA(3) structure, and send it in later:

The issue date of such an invoice is the date in field P_1. An offline invoice handed to the buyer before it gets a number carries two QR codes, "OFFLINE" and "CERTYFIKAT" (art. 106nda ust. 6 and 7 of the VAT Act). The second code needs a type 2 KSeF certificate downloaded in advance.

An online invoice sent only on the next day is treated as an offline24 invoice.

Invoices to consumers and foreign buyers

Invoices to individuals who do not run a business do not have to go through KSeF (art. 106ga ust. 2 pkt 4 of the VAT Act). The company may issue them in KSeF voluntarily.

The company issues invoices to foreign businesses, including those outside the EU, in KSeF. The buyer has no access to the system, so you hand the invoice over in an agreed way, for example as a PDF with a QR code (art. 106gb ust. 4 and 5 of the VAT Act). The receipt date is then the day the buyer actually receives it (art. 106na ust. 4).

Fines: what the law says and what the Ministry announces

Under the act, from 1 January 2027 the head of the tax office may impose a fine of up to 100% of the VAT on an invoice issued outside KSeF, or up to 18.7% of the total amount due on an invoice without VAT (art. 106ni ust. 1 of the VAT Act). The fine covers not issuing an invoice in KSeF, an offline invoice that does not follow the template, and sending an offline invoice late. Failing the KSeF duty alone does not start fiscal criminal proceedings (art. 106ni ust. 4).

On 16 September 2026 the Ministry of Finance announced that the deferral of fines will be extended to 31 December 2027. This needs a change to the act, and as of 9 October 2026 the bill has not been passed. The KSeF duty from 1 January 2027 stays unchanged, and the tax administration (KAS) says it will act on invoices issued outside the system.

Free tools from the Ministry of Finance

• Aplikacja Podatnika KSeF (online): issuing, receiving and downloading invoices as XML or PDF, permissions, tokens, certificates, UPO (the official receipt confirmation).
• Aplikacja Mobilna KSeF: issuing and receiving invoices on a smartphone.
• e-mikrofirma in e-Urząd Skarbowy (the online tax office): invoices in KSeF and transfer of them to the VAT records.

How to send the FA(3) file from the generator

You can prepare the invoice in the free KSeF invoice generator, which creates an XML file in the FA(3) structure, and send it in Aplikacja Podatnika KSeF:

1. Fill in the invoice. Set the issue date (P_1) to the day you send it and download the XML file.
2. Log in to Aplikacja Podatnika KSeF with Profil Zaufany, a qualified signature, a seal, a token or a KSeF certificate.
3. In the invoices section, choose to load an invoice and add the downloaded file.
4. Send the invoice. Once accepted, KSeF assigns it a number and the app provides the UPO.

The XML file on its own is not yet an invoice. It becomes one only once sent to KSeF (art. 106na ust. 1 of the VAT Act). If the system rejects the file, the invoice does not exist, and you send a new, correct file instead of a correction.

If you are only setting up a company, see also how to start a sp. z o.o. and what a sp. z o.o. costs.

Frequently asked questions

Must a small sp. z o.o. already use KSeF?

For purchase invoices, yes, from 1 February 2026. It may issue sales invoices outside KSeF until 31 December 2026 if their gross total in a month is no more than 10,000 zł.

Does a VAT-exempt company also issue invoices in KSeF?

Yes. It issues invoices to other businesses in KSeF under the same rules and deadlines, including the 10,000 zł limit until the end of 2026.

Will KSeF tokens expire at the end of 2026?

No. The Ministry of Finance has decided that tokens stay in KSeF 2.0 indefinitely, and they work alongside KSeF certificates.

From when must the KSeF number go in the transfer title?

For payments made from 1 January 2027, when an active VAT payer pays another active VAT payer by bank transfer (art. 108g of the VAT Act).

Will there be fines for invoices outside KSeF in 2027?

The act provides for fines from 1 January 2027. The Ministry of Finance has announced a deferral to the end of 2027, but as of 9 October 2026 that change is not yet law.