Running a business means entering into many commercial transactions, and the vast majority of them are documented with sales invoices. Traditionally, the seller is responsible for issuing the invoice, but Polish tax law also allows the buyer to issue invoices on behalf of the seller. This mechanism, known as self-billing (samofakturowanie), can be convenient in day-to-day business, especially for regular supplies.
The introduction of the mandatory KSeF (National e-Invoicing System) – from 1 February 2026 for the largest taxpayers and from 1 April 2026 for all others (Article 106ga section 1 and Article 145l of the VAT Act) – is a major change in electronic invoicing in Poland. Many businesses that have used self-billing so far wonder whether it will still be available in the new electronic system. The answer matters most for companies that have already built efficient business processes around this mechanism.
Self-billing in KSeF remains fully available to businesses that meet the relevant legal and technical conditions. The key change is the need to grant permissions in KSeF, which adds an extra layer of protection to the process of invoices being issued by the buyer
Basic legal conditions for self-billing
Self-billing is not available to every business without restrictions. The legislator has set detailed conditions that must be met for the buyer to issue invoices lawfully on behalf of the seller. These rules are meant to protect the seller's interests and to ensure that VAT is settled correctly.
Under the VAT Act, an entity buying goods or services may issue invoices on behalf of the selling taxpayer in strictly defined cases. The first is documenting an ordinary sale of goods or services to that entity. The second is advance payment invoices, which play an important role in settlements between business partners.
The third case in which self-billing is possible covers supplies of goods or services where the place of supply is the territory of a third country. This rule is particularly important for companies operating internationally
The fundamental requirement for implementing self-billing is that the seller and the buyer conclude an appropriate agreement in advance (before the invoices are issued) (Article 106d section 1 of the VAT Act). This agreement must set out the procedure for the seller to approve individual invoices. Without this element, self-billing cannot be used lawfully.
It is also important to know that invoices may be issued not only by the buyer itself, but also by a third party authorised by the seller. This may be, for example, the seller's tax representative, which gives extra flexibility in organising invoicing processes.
Self-billing agreement – key elements
Preparing the right self-billing agreement is the foundation of the whole process. Although the legislator has not provided a model form of such an agreement, it has clearly stated what it must contain. The most important element is a detailed procedure for the seller to approve invoices.
The parties to the agreement may shape the approval procedure in any way they like. There are no legal restrictions on the form or method of the seller's acceptance of invoices. The parties may agree that approval will be electronic, in writing, or even tacit, after a set period has passed.
Article 106d section 1 of the VAT Act does not specify the form of approval of individual invoices – it only requires the approval procedure to be set out in an agreement concluded before the invoices are issued. The parties should follow this procedure in practice
It is particularly important to understand the seller's responsibility in self-billing. Even if the buyer does not present an invoice for acceptance or the seller does not approve it, the seller is not released from the obligation to pay output VAT on the supply made. This rule protects the state budget against potential losses resulting from irregularities in invoicing.
In practice, many companies choose tacit acceptance, where the absence of the seller's objection within a set period means that the invoice is approved. This model is particularly convenient for regular supplies and well-established business relationships.
Implementing self-billing in the National e-Invoicing System
The introduction of KSeF has not changed the basic self-billing rules under the VAT Act, but it has added a new technical dimension to the process. KSeF works on the basis of permissions, which are granted to entities or individuals identified by their NIP (tax identification number) or PESEL (national ID number). This is a fundamental difference compared with how things worked before.
The core feature of KSeF is its permissions system, which controls access to the system's various functions. For self-billing, the most important is a separate permission for invoices to be issued by the buyer under Article 106d section 1 of the VAT Act – one of the four types of permissions listed in § 3 section 1 of the Regulation of the Minister of Finance and Economy of 12 December 2025 on the use of the National e-Invoicing System (Journal of Laws (Dz.U.) 2025 item 1815, amended by Dz.U. 2026 item 169). The seller must actively grant this permission to the buyer in KSeF. Accountants are given access in a similar way — details in our article on KSeF permissions for accounting offices.
The seller grants the self-billing permission to the buyer as an entity, not to each of its employees separately. The permission is used by the designated buyer and by the individuals and other entities that the buyer itself designates to issue invoices (§ 3 section 4 of the Regulation)
This means that the seller does not have to grant permissions to every person at the buyer's company. The employees who will issue invoices are designated in KSeF by the buyer – by a person who holds the permission to grant and revoke permissions at the buyer. This makes managing permissions much easier in larger organisations.
Permissions are granted using the KSeF interface software (§ 4 section 1 of the Regulation), for example in the free KSeF Taxpayer Application (Aplikacja Podatnika KSeF) of the Ministry of Finance or in invoicing software connected to KSeF. The seller logs in to KSeF, goes to the permissions management section and designates the buyer (including its NIP), granting it the self-billing permission.
Practical aspects of implementation – examples
To better understand how self-billing works in KSeF in practice, it is worth analysing specific business scenarios. The first example concerns a company providing services to another company which, under a self-billing agreement, issues the sales invoices.
Suppose company XYZ provides advisory services to company ABC. The companies have concluded a self-billing agreement under which ABC issues invoices on behalf of XYZ. Since KSeF was introduced, the agreement alone is not enough – XYZ must also grant ABC, in KSeF, the permission to issue invoices on its behalf, and ABC designates in KSeF the employees who will issue these invoices.
In KSeF, a self-billing agreement between the companies is not enough on its own. The buyer must also be granted the self-billing permission in the system, and the buyer then designates the people who issue invoices on behalf of the seller
The second example illustrates a more complex situation where, on the buyer's side, permissions need to be divided among many people. If a JDG (sole proprietorship) works with a larger company, it grants the self-billing permission to that company, and the company itself decides which of its employees will issue the invoices.
This flexibility of the permissions system makes it possible to create hierarchical access structures that reflect the real organisational needs of companies. An employee of the buyer who holds the permission to grant permissions can designate their colleagues independently, which greatly simplifies system administration.
The third example concerns situations where third parties, such as tax representatives or accounting offices, take part in issuing invoices. Invoices on behalf of the seller may be issued by a third party authorised by the seller (Article 106d section 2 of the VAT Act), and KSeF allows such entities to be granted the permission to issue invoices as well (§ 3 section 3 of the Regulation), provided that the seller designates them.
Advantages of self-billing in KSeF
Self-billing in KSeF offers a number of benefits that go beyond those available with traditional paper invoicing or basic electronic invoicing. The most important is the seller's real-time access to invoices issued by the buyer on its behalf.
In KSeF, the seller can immediately see the invoices issued by the buyer. This means it does not have to wait for a copy of the invoice to be sent or for confirmation that it has been issued. All invoices are available in the system in real time, which significantly streamlines accounting and control processes.
This feature makes it possible to implement a tacit acceptance procedure more effectively than before. The seller may agree with the buyer that if no irregularities are reported within a set period, the invoice is automatically approved. Thanks to real-time access to invoices in KSeF, the seller can monitor the documents being issued on an ongoing basis.
Real-time viewing of invoices in KSeF, as a rule, replaces sending invoice copies between business partners. The seller has immediate access to all invoices issued on its behalf, which significantly streamlines control and accounting processes
Another advantage is greater security of the whole process. An invoice can be issued in KSeF only by an authenticated user with the appropriate permission, and each invoice receives an identification number in KSeF. Once the number has been assigned, the content of the invoice cannot be changed – any errors are fixed with a corrective invoice, which significantly reduces the risk of invoices being forged or altered.
KSeF automatically stores all invoices for 10 years from the end of the year in which they were issued (Article 112aa section 1 of the VAT Act), which makes it easier to meet obligations related to storing accounting documents. As a rule, businesses do not have to arrange archiving of these invoices themselves – they need to do so only when the limitation period for the tax liability ends later than these 10 years (Article 112aa section 2).
Technical and organisational conditions for implementation
Implementing self-billing in KSeF successfully requires not only meeting the legal conditions, but also proper organisational and technical preparation. The first step is to analyse current invoicing processes and identify the areas that need to change with the move to the electronic system.
A key element of preparation is training the employees responsible for invoicing. People who will issue invoices in KSeF under self-billing must learn the system interface, the procedures for issuing electronic invoices and the security rules that apply in the system.
Equally important is preparing internal procedures for managing permissions in KSeF. Companies should decide who will be responsible for granting permissions, how people receiving permissions will be verified and how invoices issued under self-billing will be monitored.
Implementing self-billing in KSeF requires updating agreements with business partners and preparing new procedures for managing permissions in the system. Companies should also make sure that the employees using the system are properly trained
KSeF offers various ways of integrating with companies' internal accounting systems. Businesses can use free tools from the Ministry of Finance (including the KSeF Taxpayer Application in a web browser), invoicing software, or integrate KSeF with their ERP systems via an API. The right integration method depends on the company's profile and its technological needs.
Another important technical aspect is ensuring that the people handling self-billing have proper access to the internet and IT systems. KSeF requires a stable internet connection and up-to-date web browsers or suitable software.
Control procedures and security
Self-billing in KSeF requires appropriate control procedures to ensure the security and correctness of the whole process. Although the seller does not issue the invoices personally, it still bears full responsibility for their correctness and for settling VAT on time.
The basic control procedure should be regular verification of invoices issued by the buyer. Thanks to real-time access to invoices in KSeF, the seller can monitor the documents being issued and respond to any irregularities. This check should cover both the formal data on the invoice and the substantive accuracy of the descriptions of goods or services.
KSeF automatically checks the issuer's permissions and whether the invoice complies with the structured invoice schema – it rejects an invoice that does not comply with the schema (Article 106nd section 2 point 10(b) of the VAT Act). However, it does not check on the merits whether calculations and rates are correct, so the seller should additionally check that invoices match the actual transactions and that the correct tax rates have been applied.
The seller bears full responsibility for invoices issued by the buyer under self-billing, so it should implement effective control procedures and regularly verify the documents issued in KSeF
Proper management of permissions in the system is also an important security element. The seller should regularly review the list of entities it has authorised to issue invoices on its behalf, and agree with the buyer that the buyer keeps its employees' permissions up to date when staff change.
KSeF marks each invoice with an identification number and reports the date and time it was issued (Article 106nd section 2 points 8 and 10(a) of the VAT Act), and the seller can see the list of permissions it has granted. Sellers should review this information regularly to make sure that invoices are issued only by authorised persons and in line with the agreed procedures.
Tax and accounting settlements
Self-billing in KSeF does not change the basic rules of tax and accounting settlements, but it does bring some conveniences in documenting transactions. The seller is still obliged to settle VAT correctly on all transactions, regardless of who issued the invoice.
In KSeF, all invoices are immediately available to the tax administration, but this does not replace the VAT settlement. The seller still reports the sale in the JPK_V7 file (VAT return with records, SAF-T file), in which the KSeF number of the invoice has been given since 1 February 2026, and the buyer reports its input VAT in it. We prepare JPK_V7 files with KSeF numbers for clients who use our bookkeeping services.
For accounting purposes, invoices issued under self-billing in KSeF have the same legal force as invoices issued traditionally by the seller. They may be the basis for recording revenue at the seller and costs at the buyer, provided that all formal requirements are met.
Invoices issued under self-billing in KSeF reach the tax administration's system, but this does not release you from the obligation to file JPK_V7 – the seller reports the output VAT on these invoices in it (with the KSeF number), just as with invoices it issues itself
The seller should keep detailed records of all invoices issued by buyers under self-billing. These records should include the invoice issue date, number, amount and the date of approval by the seller.
In the event of a tax audit, the seller must be able to prove that all invoices issued under self-billing were approved by it in line with the procedure set out in the agreement. KSeF makes this easier by storing the invoices together with their issue date and KSeF number, but the seller keeps the evidence of approval (for example, correspondence) itself.
Summary of implementation conditions
For self-billing in KSeF to be used lawfully, three basic conditions must be met. First, the seller and the buyer must conclude a self-billing agreement in advance, before the invoices are issued. The law does not require written form, but an agreement on paper or in electronic form makes it easier to prove that it exists.
Second, the agreement must clearly set out the procedure for the seller to approve individual invoices. This procedure can take various forms – from explicit approval of each invoice, through tacit acceptance, to automatic approval after a set period.
Third, the seller must grant the buyer, in KSeF, the permission to issue invoices under Article 106d section 1 of the VAT Act, and the buyer must designate the people who will issue them. Without this technical step, issuing invoices in KSeF will not be possible, even if the legal conditions are met.
Below are the detailed steps for implementing self-billing in KSeF:
- Preparing and signing the self-billing agreement between the seller and the buyer
- Setting out in the agreement a detailed procedure for the seller to approve invoices
- Identifying the people who will issue invoices on behalf of the seller
- The seller logging in to KSeF and going to the permissions section
- Granting the buyer (identified by, among other things, its NIP) the permission to issue invoices on behalf of the seller
- The buyer designating in KSeF its employees who will issue the invoices
- Testing the invoicing process in KSeF
- Implementing control and invoice monitoring procedures at the seller
- Training everyone involved in the self-billing process
- Starting regular invoicing in line with the agreed procedures
| Implementation stage | Responsible | Estimated time | Key requirements |
|---|---|---|---|
| Preparing the agreement | Both parties | 1-2 weeks | Invoice approval procedure |
| Granting permissions | Seller | 1 day | Access to KSeF, buyer's details |
| System tests | Buyer | 2-3 days | Permissions in KSeF |
| Training | Both parties | 1 week | Knowledge of procedures |
Implementing self-billing in KSeF brings tangible benefits to both parties to the transaction:
- Real-time access to invoices for the seller reduces delays in accounting processes
- Automatic archiving of documents in KSeF makes it easier to meet legal obligations
- Greater transaction security thanks to electronic authentication
- The option to implement an effective tacit acceptance procedure for invoices
- Lower risk of documents being lost or damaged, because the invoices do not exist on paper
A manufacturing company working with a retail chain implemented self-billing in KSeF to streamline its settlement processes. Thanks to real-time access to invoices in the system, the company was able to introduce automatic approval of invoices 48 hours after issue, which significantly sped up the settlement cycle and improved the cash flow of both parties.
