Poland KSeF E-Invoicing Requirements 2026: Complete Guide

Last reviewed: 6 August 2026

Poland e-invoicing requirements entered their mandatory phase in 2026 through the National e-Invoicing System, known as KSeF. The largest taxpayers began issuing structured invoices through KSeF on 1 February 2026, most remaining taxpayers followed on 1 April 2026, and the obligation to receive applicable invoices through the system began on 1 February 2026.

This guide explains the rollout dates, the temporary PLN 10,000 monthly allowance, which businesses and invoices are covered, the FA(3) XML structure, online and offline modes, exclusions, storage, penalties and practical preparation steps.

Poland KSeF deadlines at a glance

The first issuing phase uses gross sales—including VAT—achieved during 2024. The threshold is more than PLN 200 million. Businesses below that threshold generally entered the issuing mandate on 1 April 2026, subject to the temporary allowance and other exclusions.

Check the official KSeF implementation dates.

What is KSeF?

KSeF stands for Krajowy System e-Faktur, or National e-Invoicing System. It is Poland’s central platform for issuing, transmitting, receiving and storing structured electronic invoices.

A typical KSeF process works as follows:

1. The supplier creates a structured invoice using compatible accounting software or a Ministry of Finance application.
2. The invoice file is transmitted to KSeF.
3. The system checks the file against the applicable logical structure.
4. If accepted, KSeF assigns a unique identification number and provides an official receipt confirmation, known as a UPO.
5. The invoice becomes available to the domestic business recipient through KSeF.
6. The system stores the structured invoice.

If the system rejects a file because it does not meet the required structure, the file is not treated as a successfully issued KSeF invoice. The issuer should correct the problem and resubmit it promptly.

What is a structured invoice?

A KSeF structured invoice is an XML file created according to the electronic template specified for the system. It contains invoice information in defined fields so that software and the tax administration can process the data automatically.

From 1 February 2026, Poland uses the FA(3) logical structure for structured invoices. It replaced FA(2), which applied through 31 January 2026. FA(3) is also used for correction invoices and final invoices issued from 1 February 2026, even when the original or advance invoice used an earlier structure.

An ordinary PDF, paper invoice, scanned document or image does not become a KSeF structured invoice simply because it was created electronically. A business may create a readable visualization for a customer or employee, but the structured XML submitted to KSeF is the legally important system file.

Read the official English FA(3) information sheet.

Who must use KSeF?

The issuing mandate broadly covers taxpayers with a registered office or relevant fixed establishment in Poland when they issue invoices that fall within the Polish rules. It can apply to businesses that are active VAT taxpayers as well as taxpayers benefiting from a VAT exemption.

The Ministry of Finance explains that taxpayers exempt from VAT on a subjective or objective basis are generally included. For example, a business using a turnover-based VAT exemption does not automatically avoid KSeF. Its entry date and the PLN 10,000 transition still need to be checked.

Foreign businesses and fixed establishments

A taxpayer without a business establishment or fixed establishment in Poland is generally outside the mandatory issuing scope. A foreign taxpayer with a Polish fixed establishment can also be excluded for a transaction when that establishment does not participate in the supply.

Foreign businesses may be able to issue certain invoices through KSeF voluntarily. Fixed-establishment analysis is fact-specific, so international businesses should review the Polish Ministry of Finance guidance and obtain appropriate advice.

Review the official scope of mandatory KSeF.

How the PLN 10,000 monthly allowance works

Until 31 December 2026, a taxpayer otherwise required to issue through KSeF may issue applicable paper or electronic invoices outside the system when the total gross sales documented by those relevant invoices in a month does not exceed PLN 10,000.

This is a temporary transition, not a permanent small-business exemption. Several details are important:

• the calculation uses the gross value, including VAT;
• only invoices that would otherwise be subject to mandatory KSeF count toward the limit;
• B2C invoices and other excluded invoices do not count toward this particular threshold;
• the relevant month is based on the invoice’s issue date;
• once the threshold is exceeded, the invoice that causes the excess must be issued through KSeF; and
• after exceeding the limit, the taxpayer continues using KSeF for subsequent covered invoices and cannot return to the allowance merely because a later month is below PLN 10,000.

For example, if a small business issues covered invoices totalling PLN 8,000 in April, it may remain outside KSeF under the transition. If a May invoice takes the total above PLN 10,000, that threshold-crossing invoice and the following covered invoices should be issued through KSeF.

The allowance does not delay receiving. Even a business that qualifies to issue outside KSeF until the end of 2026 may need to receive supplier invoices through the system from 1 February 2026.

Read the Ministry’s PLN 10,000 guidance and examples.

Invoices and documents outside mandatory KSeF

Not every invoice or accounting document is transmitted through KSeF. Important exclusions or separate treatments include:

• consumer invoices: invoices to private individuals not carrying on business are outside mandatory KSeF;
• certain foreign transactions: the parties’ establishment and fixed-establishment status can remove the issuing obligation;
• pro forma invoices: these are not VAT invoices and are not transmitted to KSeF;
• internal documents: internal evidence and similar accounting documents are not KSeF invoices;
• debit and credit notes that are not VAT correction invoices: these are not sent as structured invoices;
• cash-register invoices and simplified receipts: transitional rules permit specified cash-register invoices and receipts with a buyer NIP up to PLN 450 or €100 to remain outside mandatory KSeF through the end of 2026; and
• specified special invoice categories: separate regulations can exclude particular transactions or documents.

Poland abolished the former correction-note rules from 1 February 2026. Businesses should not assume that an old correction-note process can continue unchanged inside or outside KSeF. Correction invoices must follow the appropriate current process.

Receiving invoices through KSeF

Receiving through KSeF became mandatory on 1 February 2026 for covered entities, including businesses whose own issuing obligation began later or that use the temporary PLN 10,000 allowance.

A domestic buyer with a Polish NIP normally obtains its supplier invoice through the system. Businesses should establish who monitors incoming invoices, who checks them, how they enter accounting records and how disputes or incorrect data are handled.

A KSeF invoice does not require a customer to wait for a paper original. The structured file and system data provide the authoritative record. Businesses may still use a readable visualization for internal approval.

Online and offline modes

Online mode

In online mode, the invoice XML is transmitted to KSeF in real time. After acceptance, the system provides the KSeF number and UPO. Businesses should monitor technical responses rather than assuming that sending a file means it was accepted.

Offline24 mode

Offline24 allows a taxpayer to prepare an invoice without a live KSeF connection and send it to the system no later than the next working day. For a domestic recipient who receives through KSeF, the supplier should not treat an offline draft as a substitute for completing the required system transmission.

System unavailability and failure

Separate procedures apply when KSeF is officially unavailable or has a declared failure. Submission deadlines and delivery requirements can differ from ordinary Offline24 use. Accounting software should distinguish these modes and preserve the information needed to transmit the file when the system becomes available.

Read the official online and offline explanation.

KSeF numbers, UPOs and QR codes

The supplier’s own sequential invoice number and the KSeF identification number are different. The supplier continues using its invoice-numbering system, while KSeF assigns an additional system identifier after successful acceptance.

The UPO confirms successful transmission and contains important system information. Businesses should store it or ensure it can be retrieved with the corresponding invoice.

When a structured invoice is used or delivered outside KSeF in a situation covered by the rules, its visualization may need a verification link or QR code. The QR code can allow the recipient to access the invoice in KSeF and verify its data. It is also important for certain recipients without a Polish NIP and for invoices created in offline modes.

Consult the official KSeF QR-code guidance.

How businesses access KSeF

Businesses can use compatible commercial accounting software connected to the KSeF 2.0 API or free tools supplied by the Ministry of Finance. The official tools include the KSeF Taxpayer Application and KSeF Mobile Application.

The taxpayer must also manage authentication and permissions. Access can be granted to employees, accountants and other authorised persons according to their responsibilities. KSeF certificates support authentication and offline processes.

Certificates and credentials should be protected like other sensitive financial access information. Do not share them through ordinary email or assign broad permissions when a more limited role would be sufficient.

Read the official KSeF certificate guidance.

Invoice storage and retention

KSeF stores structured invoices for 10 years, calculated from the end of the year in which the invoice was issued. During this period, the system provides access to the structured record.

A business may still need its own archive for operational continuity, attachments, records not stored in KSeF or legal retention that extends beyond the system’s 10-year period. Export and backup procedures should be agreed with the accountant and software provider.

Penalties and deferred 2026 obligations

The Ministry states that monetary penalties for specified KSeF failures will apply from 1 January 2027. Potential failures include not issuing through KSeF when required, using an incorrect form during a failure or unavailability period, and missing the deadline to submit an offline invoice.

The obligation to include a KSeF invoice number in specified business-to-business payment references and split-payment arrangements is also deferred through the end of 2026 under the current timetable.

The temporary absence of monetary penalties during 2026 does not make the issuing requirement optional. Businesses should use the transition to correct processes and should not intentionally ignore the mandate.

Review the Ministry’s current rules and penalty timetable.

How to prepare for KSeF

1. Confirm the applicable start date. Check 2024 gross sales and whether the business entered on 1 February or 1 April 2026.
2. Review the monthly allowance. If relying on the PLN 10,000 transition, track only covered gross invoice sales and create an alert before the limit is exceeded.
3. Map invoice types. Separate domestic B2B, B2C, foreign, cash-register, correction and exempt documents.
4. Choose a technical route. Decide whether to use an official free application, commercial accounting software or an API integration.
5. Configure FA(3). Ensure the software uses the current XML structure and correctly maps mandatory and conditional fields.
6. Assign permissions. Authorise staff and external accountants according to their duties.
7. Protect certificates. Store credentials securely and plan renewal, revocation and incident procedures.
8. Test responses. Confirm how the system reports acceptance, rejection, the KSeF number and UPO.
9. Plan offline operation. Document Offline24, unavailability and failure procedures, including submission deadlines and QR codes.
10. Train teams. Sales, accounting, purchasing and customer service should understand how KSeF changes invoice delivery and correction.

Common mistakes to avoid

• Uploading a normal PDF. KSeF uses the structured FA(3) XML format.
• Assuming VAT exemption removes the mandate. VAT-exempt taxpayers can still be required to use KSeF.
• Ignoring incoming invoices. Receiving started for covered entities on 1 February 2026.
• Misusing the PLN 10,000 allowance. Once a threshold-crossing invoice occurs, subsequent covered invoices must remain in KSeF.
• Counting every sale toward PLN 10,000. The calculation covers invoices otherwise subject to KSeF, not consumer and other excluded invoices.
• Confusing invoice numbers. The supplier’s invoice number is different from the KSeF number.
• Assuming a sent file was accepted. Check the system response and UPO.
• Sharing certificates carelessly. KSeF access can expose sensitive financial information and issuing authority.

Frequently asked questions

Is KSeF mandatory in Poland in 2026?

Yes. The issuing obligation began on 1 February 2026 for taxpayers with more than PLN 200 million in gross 2024 sales and on 1 April 2026 for most others. Qualifying small issuers can use the temporary monthly PLN 10,000 allowance through the end of 2026.

Do businesses need to receive KSeF invoices?

Covered entities have needed to receive applicable invoices through KSeF since 1 February 2026, even if their own issuing date was later or they use the small-issuer transition.

Is a PDF a valid KSeF invoice?

No. A KSeF structured invoice is an XML file created according to FA(3). A PDF can serve as a readable visualization but does not replace the structured system file.

Are VAT-exempt businesses included?

Yes, VAT exemption does not automatically remove a taxpayer from the issuing mandate. The business should check its start date, transaction scope and possible PLN 10,000 transition.

Are consumer invoices sent through mandatory KSeF?

Invoices to consumers are outside the mandatory KSeF scope. If KSeF is used voluntarily for a recipient without a NIP, the supplier must follow the access and QR-code rules that apply.

What happens when monthly covered invoices exceed PLN 10,000?

The invoice that causes the gross monthly total to exceed PLN 10,000 must be issued through KSeF. Following covered invoices must also use KSeF, and the taxpayer does not return to the allowance in a later lower-sales month.

Does KSeF store invoices?

Yes. Structured invoices are stored in KSeF for 10 years from the end of the year in which they were issued. Businesses may retain additional archives for other operational or legal needs.

Are penalties already applied in 2026?

The monetary penalties specifically described for KSeF failures are scheduled to apply from 1 January 2027. The legal obligation still applies during 2026, so businesses should not treat the penalty transition as permission to ignore KSeF.

Is Peppol required for KSeF?

KSeF is Poland’s central national system and is not the same as Peppol. A business may use software that supports multiple networks, but covered Polish invoices must follow the KSeF process.

Official sources

• Polish Ministry of Finance: official KSeF portal
• Scope and deadlines for mandatory KSeF
• Official PLN 10,000 transition guidance
• Official English FA(3) structured-invoice guide

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Visit the Invoice Mandates homepage for international electronic-invoicing deadlines. You can also compare Poland with our guides to Germany e-invoicing requirements, France e-invoicing requirements and Belgium e-invoicing requirements.