KSeF for a Sole Proprietorship (JDG) in Poland in 2026 — the Obligation, Invoices, and Offline Modes

The Obligation Deadlines

• February 1, 2026 — taxpayers whose value of sales including VAT exceeded 200 million zł in 2024,
• April 1, 2026 — the remaining taxpayers covered by the obligation,
• January 1, 2027 — the end of the transitional relief for the smallest issuers.

Through the end of 2026, a taxpayer may issue invoices outside KSeF if the total gross value of sales documented by such invoices does not exceed 10,000 zł per month. Once the limit is exceeded, the obligation arises under the transitional rules.

This is not a permanent exemption from KSeF, nor a limit on the company's entire turnover.

Who the System Covers

The obligation applies primarily to taxpayers established in Poland and to foreign taxpayers with a fixed place of business in Poland, if that place takes part in the transaction.

The PIT form — lump-sum, tax scale, or flat tax — does not determine the scope of KSeF. The system can cover both active VAT taxpayers and taxpayers who benefit from an exemption.

What Falls Outside Mandatory KSeF

Important exclusions include, among others:

• invoices issued to consumers — B2C,
• invoices issued by a foreign taxpayer with no seat and no relevant fixed place of business in Poland,
• documents and situations excluded by special rules or covered by transitional arrangements.

You should not, however, use the shortcut "a foreign invoice is outside KSeF." A Polish issuer covered by the obligation may issue an invoice for a foreign counterparty in KSeF.

What a Structured Invoice Is

The invoice is transmitted to KSeF as an XML file compliant with the FA(3) structure. A PDF is only a visualization of the data and does not replace a structured invoice where KSeF applies.

The invoice keeps its own number assigned by the seller. KSeF additionally assigns it a unique KSeF number. It is a mistake to claim that the KSeF number replaces the entrepreneur's invoice number.

In online mode, the issue date is the date on which a correct invoice is transmitted to the system in accordance with the statutory rules. Once accepted, the system assigns the KSeF number and makes the UPO available.

How to Issue an Invoice

1. Grant permissions to yourself, your accountant, or a program.
2. Prepare the invoice data in the current FA(3) structure.
3. Transmit the document through the Ministry of Finance application or an integrated program.
4. Check the processing status.
5. Retrieve the KSeF number and UPO once the document is accepted.
6. If the buyer does not use KSeF, provide them with the invoice in the agreed form with the correct QR code where required.

A technical rejection means the invoice was not issued in KSeF. You have to correct the error and resend the document.

How to Receive an Invoice

An invoice issued in KSeF for a Polish NIP is available to the buyer without a separate "acceptance." The system does not work like an inbox with a button to accept or reject an invoice.

The buyer should:

• retrieve the document,
• check the seller, the amounts, and the subject of the purchase,
• establish the connection with the business,
• check the right to the cost and to the VAT deduction,
• ask the seller for a correction if the data is wrong.

The mere presence of an invoice in KSeF does not automatically result in booking, payment, or the right to deduct VAT.

KSeF Does Not Replace JPK_V7

KSeF supplies the administration and programs with data from invoices, but it does not file JPK_V7 on the taxpayer's behalf. The declaration and records also cover events that do not arise directly from KSeF invoices, corrections, the import of services, and other items.

Accounting software can automate the preparation of JPK, but responsibility for the completeness of the settlement remains with the taxpayer.

Invoices from and to Abroad

Purchase invoices from a foreign seller with no Polish seat or fixed place of business will usually not appear in KSeF. You have to receive them in the existing form and pass them to accounting.

A Polish seller covered by KSeF can, however, issue an invoice for a foreign buyer in the system. The buyer receives it outside the system in the agreed form, with the required access marking.

The scope depends on the issuer's status, their place of business, and the type of document — not on the buyer's country alone.

Invoices for Consumers

B2C invoices are outside mandatory KSeF. The seller may use the system voluntarily under the rules provided by the regulations, but the consumer must receive the document in an accessible form.

A consumer should not be confused with a VAT-exempt entrepreneur. A JDG buying on its NIP does not become a consumer just because it does not deduct VAT.

Offline Mode and Outages

The rules provide for modes that allow invoices to be issued outside a live connection to the system, including offline24 and procedures for periods when KSeF is unavailable.

In such cases you have to:

• create an invoice compliant with the structure,
• mark it with the required QR code,
• pass it to the buyer,
• transmit it to KSeF within the deadline applicable to the given mode.

The deadlines differ depending on whether it is the taxpayer's choice, a system outage, or unavailability on the entrepreneur's side. All situations should not be reduced to the rule "I'll send it once I get the internet back."

Permissions

In a JDG, the owner can authenticate electronically and grant permissions to further people or entities. In companies and some other organizations, a ZAW-FA filing may be needed if there is no qualified stamp containing the NIP.

Private login credentials should not be handed to your accountant. Instead, they are granted the appropriate permissions to work on the taxpayer's behalf.

Corrections

The buyer does not reject a faulty invoice in KSeF. The seller issues a correcting invoice. A correction note does not function in mandatory KSeF the way it did in the old paper workflow.

The moment a correction is recognized in VAT and PIT depends on the reason for and type of correction — the date the document appears in the system alone does not settle all the consequences.

Penalties and the Transitional Period

Sanctions for failing to issue an invoice in KSeF have been deferred to 2027. This does not mean the obligation can be ignored in 2026. An invoice issued in breach of the mandatory mode can cause evidentiary, operational, and tax problems.

The amount of any future penalty depends on the circumstances and the statutory limits. Not every irregularity automatically means a penalty equal to 100% of VAT.

Storage

KSeF stores invoices for 10 years, counted in line with the statutory rules. It is still worth keeping supporting documents, contracts, protocols, orders, and evidence that an expense is connected with the business — KSeF does not store these as part of the invoice.

Most Common Mistakes

1. Treating a PDF as a structured invoice.
2. Assuming the KSeF number replaces your own number.
3. Expecting an "accept" or "reject" button.
4. Automatically booking every invoice from the system.
5. Assuming KSeF sends JPK_V7.
6. Excluding every foreign invoice.
7. Overlooking invoices from foreign suppliers that are not in KSeF.
8. Having no procedure for offline mode and outages.
9. Handing your accountant login credentials instead of permissions.
10. Treating the 10,000 zł limit as a permanent exemption.

Sources

• KSeF — the Ministry of Finance official portal
• KSeF 2.0 Handbook
• KSeF FAQ

Need to Implement KSeF in Your JDG?

Oxyok receives, checks, and books invoices and keeps JPK_V7. Accounting costs from 49 zł + VAT per month.

Write to Paweł or see Oxyok accounting.

This material is general in nature. KSeF is being rolled out in stages, and the scope depends on the status of the issuer, the buyer, and the type of invoice.