National e-Invoice System (KSeF) Q&A

As of 1 February 2026, KSeF will be obligatory for entities whose turnover in the previous year exceeded PLN 200 million, and as of 1 April 2026 – for all entrepreneurs.

Mandatory integration with the system will apply to taxpayers having their registered office or fixed establishment in Poland and obliged to issue issue VAT invoices to Polish and foreign entrepreneurs.

What is particularly important when adapting the processes currently in force in the organisation and preparing the enterprise for the changes under which uploading an invoice to KSeF will become mandatory, now – within the period from 1 January 2022 to 31 January 2026 – all entities can voluntarily use the KSeF system.

In addition, until 31 December 2026, it will still be possible to issue invoices outside of KSeF (in paper or electronic form) if the total amount of sales in a given month, VAT included, does not exceed PLN 10,000 on such invoices.

The mandatory e-invoicing in Poland and the introduction of KSeF will bring several benefits, which will be both financial (reducing the waiting time for refund of VAT overpayment from 60 to 40 days) and organizational (faster document circulation, no risk of document loss/destruction, exemption from the obligation to store and archive invoices up to 10 years).

In order for all structured invoices to be issued correctly, companies doing business in Poland should adapt their internal procedures related to document circulation and the invoicing process.

First of all, it is important to determine the method of delivering invoices issued in the KSeF system if the recipient of these structured invoices is a foreign contractor.

Another area requiring action is the analysis of the compliance of the accounting systems used with the KSeF requirements and their possible adaptation.

Additionally, employees who are currently involved in the invoicing process should also be trained. All people who come into contact with data, customers and contractors – not only those who have the ability to issue invoices – should be familiarized with the new Polish regulations and learn about the consequences of failure to comply with them.

The obligation to issue invoices in KSeF will apply to VAT payers with their registered office or fixed place of business in Poland.
Foreign entities that are at risk of establishing a fixed place of business, but at the same time have arguments in favor of its absence, should consider submitting an application for an individual interpretation in this respect.

The obligation to issue invoices in KSeF will not apply to invoices issued by:

• taxpayers who have neither their registered office nor a fixed place of business in Poland*;
• taxpayers who do not have their registered office in Poland or who have a fixed place of business in Poland, but this fixed place of business does not participate in the supply of goods or the provision of services*;
• taxpayers who use the OSS and IOSS special procedures;
• taxpayers who issue invoices only to natural persons who do not run a business.

*Such taxpayers will still be able to issue invoices in the KSeF system voluntarily.

Issuing e-invoices in Poland will not be obligatory for entities that do not have a fixed place of business in Poland (within the meaning of VAT regulations).

An entity that does not have a fixed place of business in Poland is not obliged to collect purchase invoices in the KSeF system. In the case of a transaction, it informs its Polish contractors about this fact and indicates how to deliver the invoice.

In the Polish KSeF system, it is possible to download invoices without the need to log in – in anonymous access mode. The seller using this option should then inform his contractor about the invoice number, the invoice system number and the invoiced gross amount.

Ultimately, anonymous login is to be replaced by placing structured QR codes on invoices, which will allow to review the invoice marked with the code.

In the case of legal entities, it is necessary for taxpayers to authenticate in the system. The authentication may be made using a qualified seal or by submitting a ZAW-FA form.

After designating the persons who will be authorised to use KSeF on behalf of the company, they will be able to authenticate using a trusted signature, qualified electronic signature, KSeF certificate and – until the end of 2026 – token.

Electronic structured invoices are – in simple terms – invoices issued using the National e-Invoice System.

This is a type of e-invoice that contains information specified in the regulations, has a specific form and is saved in a specific electronic format (XML). This format must meet the conditions necessary to properly read and process the data contained in the document. Additionally, an e-invoice in Poland must include a KSeF number – i.e. an identification number assigned to the document by the system.

E-invoicing in Poland is pretty straightforward. In order to issue a structured invoice in the accounting system, it is necessary to perform the following steps:

• first, as usual, the taxpayer prepares an invoice – or invoices – in the company's accounting system;
• then the person authorized to log in and authorized by the system logs in to KSeF;
• the next step is to send an e-invoice or a package of e-invoices via API to the KSeF system;
• now the KSeF system will automatically verify the entity and the compliance of the invoice with the template;
  • after positive verification the KSeF system will assign a number identifying the structured invoice – the so-called KSeF invoice number – and the invoice will be able to be downloaded from the system by the contractor
  • in the event of negative verification the invoice will be rejected (this may happen when the document is inconsistent with the invoice template or when the system is unavailable).

The KSeF system also allows you to skip the first of the steps mentioned here and issue a structured invoice directly there, so taxpayers do not have to use the accounting system.

Issuing e-invoices and sending them to KSeF requires adapting the accounting program in such a way that it is possible to redirect and send documents directly to this central invoice database.

An alternative way to send an invoice to KSeF is to use free tools provided by the Polish Ministry of Finance. Taxpayers can therefore use the e-Mikrofirma program or directly log in to the KSeF system and use it to prepare and send an invoice.

The obligation to upload invoices to KSeF is assigned to the person (or persons) authorised to perform such activities on behalf of the company. The person representing the company is therefore obliged to grant appropriate authorisations to the staff responsible for the invoicing process. The authorised person can be reported in one of the following ways:

• in a notice to grant authorisations (submitted to the competent head of the tax office), on a ZAW-FA form;
• using a qualified seal;
• via the interface software available on the website of the Polish Ministry of Finance.

From February or April 2026, printouts (or electronic images) of structured invoices provided by the taxpayer to the buyer will have to contain a QR code with the data of the structured invoice, allowing it to be identified in the system.

From July 2024*, the recipient's consent to receiving structured invoices via KSeF will not be required – except for cases where the seller issues invoices to entities not obliged to use the KSeF system.

However, until the end of June 2024, the buyer has the right not to consent to receiving e-invoices in the KSeF system. In this case, such an invoice should be generated and delivered to the buyer in another way agreed with him.

* Currently the date of entry into force of the regulations has been postponed.

In general, the key factor is not the date of creation of the invoice in the accounting system, but the moment of its appearance in the electronic database. This means that the invoice is considered issued in KSeF only on the day it is transmitted.

The information about the transmission date – and therefore the issue date – will be visible in the Official Confirmation of Receipt (UPO), and the invoice issue date itself will also be an element of the invoice number assigned by KSeF.

In addition, the legislation provides for an Offline 24 mode which makes it possible to issue invoices outside of the system and transmit them to KSeF without delay (on the next working day at the latest). In such a case, the issue date is considered to be the date indicated on the invoice by the taxpayer.

From February 2026, if an invoice is issued in KSeF, the issuer will not be obliged to send the invoice outside of the system.

If a structured invoice is issued to a buyer who is not obliged to use the KSeF system, the taxpayer must obtain consent from the contractor to receive the invoice using the National e-Invoice System. If the contractor does not agree to receive the invoice in the system, the issuer will be obliged to deliver the invoice in another way agreed with him.

In the event of a failure or technical break which is announced on the website of the Public Information Bulletin (BIP) and communicated through the interface software, the taxpayer issues invoices according to the template.

Within 7 business days from the end of the KSeF failure, the taxpayer is obliged to upload these invoices to the system. Such invoices will be specially marked to indicate that they were issued during the period of failure.

In the case of a KSeF technical break, the taxpayer is obliged to issue invoices according to the template and then to upload these invoices to KSeF not later than on the next working day after the day on which the system became available again.

Additionally, there is an Offline 24 mode available, which is not an emergency mode as such, but makes it possible to issue invoices consistent with the FA logical structure outside of KSeF and to transmit them to the system without delay (on the next working day after issuing the invoice at the latest). Each taxpayer will be able to use the Offline 24 mode, as no limits in this regard are stipulated in the law. This mode was proposed in response to taxpayers’ worries about the prolonged waiting time for processing invoices in KSeF.

The Ministry of Finance will make it possible to attach documents to structured invoices concerning activities involving complex data. However, it is worth noting that the extent of the data which attachments to invoices can contain will be highly limited.

To be able to transmit e-invoices with attachments, it is necessary to submit to the Head of the National Revenue Administration a notice of the intention to issue and transmit to KSeF invoices with attachments. The notice can be submitted through the e-Tax Office (e-Urząd Skarbowy) account. Invoices with attachments can be issued after receiving the confirmation that invoices with attachments can be issued and transmitted to KSeF.

Importantly, to stop issuing invoices with attachments in KSeF, this fact must also be reported to the Head of the National Revenue Administration.