Self-billing in the National e-Invoicing System in Poland (KSeF) and VAT deduction

Self-billing in the National e-Invoicing System in Poland (KSeF) remains permissible, but after the individual tax ruling issued by the Director of the National Revenue Information (KIS) on 27 February 2026, this procedure can no longer be treated merely as a convenient organisational solution. The dispute is not about whether invoices may be issued by the buyer on behalf of the seller. The real issue arises at the invoice approval stage and concerns when and in what form that approval should be given. This is precisely where the Polish tax authority has adopted a much stricter position than would appear from the wording of the Polish VAT Act itself.

For businesses in Poland, the key point today is to distinguish between two different layers. The first is the wording of the law, which requires an agreement between the parties and an invoice approval procedure, but does not describe the technical model of approval in detail. The second is the current interpretative practice of the tax authorities, from which it follows that the seller should approve the XML file before the invoice is sent to the KSeF. If a company uses self-billing on a large scale, that difference is no longer only formal. It becomes an operational and tax risk issue.

In practice, the topic is no longer limited to whether the buyer has the right authorisations within the system. It is equally important whether the business can demonstrate that its invoice approval model is consistent with the law, the wording of the contract and the current level of interpretative risk in Poland. For that reason, after the rollout of the mandatory KSeF, self-billing should be reviewed not only by the accounting team, but also by people responsible for tax, document workflow and contractor relations.

In companies that want to organise document workflow and invoice approval more effectively in the National e-Invoicing System in Poland (KSeF) environment, a useful solution may be Customer Invoice Portal by getsix®, which supports the submission of documents to accounting, their verification and more transparent management of the approval process.

What is self-billing?

Self-billing means that the buyer of goods or services issues an invoice in the name and on behalf of the seller. The legal basis is Article 106d(1) of the Polish VAT Act. Under this provision, such a model is allowed provided that the parties have concluded an agreement in advance and that the agreement defines the procedure for the seller to approve individual invoices. The law therefore does not remove the seller’s control over the document. On the contrary, it clearly assumes that the buyer may invoice on the seller’s behalf only within an agreed approval mechanism.

In addition, an invoice issued under the self-billing procedure must contain the wording “self-billing”. This follows from Article 106e(1)(17) of the Polish VAT Act. This requirement is not merely formal. It makes it clear that the document was issued by the buyer under a special procedure, in a model where the later confirmation of the invoice content by the seller becomes particularly important.

In practice, self-billing is used mainly where a business wants to organise high-volume document flows, speed up settlements with contractors or reduce the risk of delays on the side of suppliers and subcontractors. For years, this mechanism has functioned in business practice in Poland as a useful and, in principle, tax-neutral solution, provided that the parties had actually concluded an agreement and genuinely applied an approval procedure. That practical convenience does not, however, remove the need to document the entire process correctly.

It is also worth remembering that the mere possibility for the buyer to issue an invoice does not mean complete freedom. Under Article 88(3a)(5) of the Polish VAT Act, invoices issued by the buyer in accordance with separate provisions but not accepted by the seller do not provide a basis for reducing output VAT or obtaining a refund of input VAT. That provision is now central to the risk assessment for businesses using self-billing in Poland.

Self-billing in KSeF in Poland – have the rules really changed?

According to the official materials of the Polish Ministry of Finance, the self-billing mechanism in the National e-Invoicing System in Poland (KSeF) was supposed to remain the same as before. The Ministry expressly states that the buyer may still issue invoices on behalf of the seller if the parties have concluded the relevant agreement, and that the main change is the need to grant the proper permissions within the system. The Ministry also emphasises that the self-billing mechanism itself and the related VAT consequences remain unchanged.

At the same time, the Polish Ministry of Finance has stressed that 2026 is a transitional period, and that penalties are not imposed during this time for errors connected with the use KSeF. That does not mean, however, that every procedural error is neutral from the perspective of the right to deduct VAT in Poland.

The absence of system penalties for implementation errors does not eliminate tax risk if the authority concludes that an invoice issued under self-billing was not approved correctly. In other words, a business may avoid sanctions for the way it uses the system and still enter into a dispute over the deduction of VAT from a specific document. These are two separate areas of assessment.

That is why, after the introduction of the mandatory National e-Invoicing System in Poland (KSeF), self-billing must be analysed more broadly than before. The system has not abolished the procedure, but it has significantly increased the importance of the technical form of the invoice, the approval method, the audit trail and the sequence of actions. For companies issuing many such documents, this may mean a substantial redesign of internal processes.

What should invoice approval look like in self-billing?

At statutory level, the answer is not as detailed as the Polish tax authorities would like it to be. Article 106d(1) of the Polish VAT Act requires the agreement to specify the procedure for approving individual invoices by the taxpayer making the sale, but it does not directly indicate the form of approval, the communication channel or the moment at which the approval must occur. The Act also does not say that the approval must concern only the XML file.

For that reason, for many years the dominant approach in Poland was that the parties had significant contractual freedom in this area. They could therefore agree that approval would be active or passive, would take place in a document workflow system, by email or through the absence of objections within a defined period. In practice, what mattered most was whether it was possible to demonstrate that the seller had approved the invoice issued by the buyer. The Act itself did not create a rigid technological model.

After the launch of KSeF, that flexibility was not expressly removed by the new wording of the legislation. The official materials of the Polish Ministry of Finance still indicate that self-billing works in the same way as before and that the only change is the need to grant the buyer appropriate permissions in the system. This is an important argument because it shows that, at the level of official guidance, the emphasis was placed more on access management than on introducing a new and formalised invoice content approval model.

That does not mean businesses can treat the issue lightly. In KSeF, the invoice exists as an XML file, and the KSeF number is assigned automatically by the system after the e-invoice is sent and accepted into the platform. That number is not part of the XML file itself. As a result, the moment when the document is sent to the system and the moment when it formally comes into legal circulation are now highly relevant for assessing whether the approval procedure has been implemented correctly.

The restrictive position of the tax authority in the KIS ruling of 27 February 2026

The heart of the dispute is the individual tax ruling issued by the Director of the National Revenue Information (KIS) on 27 February 2026, reference 0112-KDIL1-3.4012.874.2025.2.KK. The case concerned a company that used self-billing in cooperation with its subcontractors, all of whom were active VAT taxpayers in Poland. The company issued invoices in their name and on their behalf, and the procedure was governed by contracts. Once the company became subject to mandatory use of the National e-Invoicing System in Poland (KSeF), the question arose how such approvals should be organised correctly.

The taxpayer argued that, since the Polish VAT Act does not specify the approval method in detail, a solution should also be acceptable in which the contractor approves the invoice after it has been sent to KSeF. Alternatively, the company considered sending contractors an earlier PDF draft of the invoice, containing the essential transaction data but not yet the KSeF number and not yet the final structured form. The tax authority rejected both of these approaches.

According to the Director of the National Revenue Information (KIS), approval should occur immediately before the invoice is introduced into legal circulation, which in practice means before the XML file is sent to KSeF. The authority also stated that what should be presented to the seller for approval is the invoice content in XML format, not a PDF draft. The ruling further stressed that approval may be active or passive, but it must concern the XML content and must take place before the invoice is submitted to the system.

This is a highly demanding position for businesses. In practice, it means that the process must be structured so that the seller approves the document before it is transmitted to KSeF. For companies processing high volumes of invoices, this may create a major operational burden, slow down document circulation and require new control steps.

Why this position raises serious doubts

The most important problem is that the Polish VAT Act does not expressly require approval of the XML file only, nor does it clearly impose the obligation for approval to take place before the invoice is effectively issued in the National e-Invoicing System in Poland (KSeF). The provision refers to a procedure for approving individual invoices, but does not resolve whether this should be a stage preceding the document’s issuance in the system or part of a later review of an already generated invoice. That is precisely why the authority’s restrictive interpretation raises legitimate doubts.

An additional argument is that the official communications of the Polish Ministry of Finance at the same time emphasise that self-billing in KSeF works as before and that the only change is the granting of the relevant system permissions to the buyer. If the legislator had really intended to introduce a new and strict obligation to approve the XML in advance, one would expect that principle to be reflected more clearly either in the legislation itself or in the official implementation guidance. At present, such clarity is missing.

The doubts are also practical in nature. XML is a technical format and is not always convenient for human review. Of course, it is possible to create a readable visualisation of the data contained in such a file, but in its ruling the authority clearly distinguished between the XML itself and a PDF draft. This creates tension between the way the system technically operates and the realities of everyday document workflow in a business environment.

It is also important not to confuse two separate issues: the transitional period without penalties for mistakes in using the National e-Invoicing System in Poland (KSeF), and the security of the right to deduct VAT. The absence of system penalties in 2026 does not automatically mean that an incorrectly designed self-billing process is tax-neutral. That is why businesses should treat the KIS ruling as a serious warning signal, even if they disagree with its direction.

Risk of losing the right to deduct VAT – where is the real threat?

Today, the greatest risk is not that self-billing as such will become impermissible in Poland. The real risk arises where the tax authority concludes that the invoice issued by the buyer was not approved correctly. In that case, the authority may rely on Article 88(3a)(5) of the Polish VAT Act and challenge the right to deduct input VAT from that document. This is exactly the mechanism linked by the KIS ruling of 27 February 2026 to a defective approval procedure.

In practice, the risk may be especially real where a company:

• obtains the contractor’s approval only after the invoice has been effectively sent to the National e-Invoicing System in Poland (KSeF),
• sends for approval only a PDF or another visualisation rather than the content of the structured invoice,
• cannot demonstrate when and how the seller approved the document,
• has a very general self-billing clause in the contract, while in practice operating under a different and undocumented model.

At the same time, it would be too far-reaching to say that every company currently using a PDF-based approval model automatically loses its right to deduct VAT. A more accurate conclusion is that there is now an increased interpretative dispute risk, because the KIS ruling is an individual interpretation and is not a source of universally binding law in Poland. Even so, from a practical perspective businesses should not ignore it, because it may shape the direction of future audits and further rulings.

What should a business do in practice?

Analysing the legislation and the ruling alone is not enough. In self-billing after the rollout of the National e-Invoicing System in Poland (KSeF), the crucial issue is whether the company’s procedure is consistent, documented and defensible in the event of a tax audit. In practice, this area should be reviewed step by step.

1. Review self-billing agreements

The first step should be to review the existing contracts with contractors. In many cases, these agreements were drafted before the introduction of KSeF and do not reflect the reality of structured invoices. If an agreement only contains a general reference to invoice approval but does not specify the sequence of actions, the method of confirmation or the deadlines, it is worth refining it.

It is particularly important that the contract clearly states:

• who issues the invoice on behalf of the seller,
• how the seller approves the invoice content,
• whether the approval is active or passive,
• within what timeframe the contractor may raise objections,
• what the consequences are if no response is received within the agreed period.

2. Check how the document workflow actually operates

In many businesses, the biggest issue is not the wording of the contract itself, but the gap between what the contract says and what happens in practice. That is why it is worth reviewing the actual process and determining whether it corresponds to the current tax risk environment in Poland.

In practice, the company should verify:

• who prepares the invoice data,
• who generates the document before it is sent to the National e-Invoicing System in Poland (KSeF),
• in what form the document is submitted to the contractor for approval,
• where the approval evidence is stored,
• whether the exact moment of approval can be established without doubt.

3. Assess whether the current procedure should be tightened

Even if the business considers the KIS position too restrictive, it is still worth assessing whether the current model should be temporarily adjusted to reflect a more cautious approach. This is especially relevant for companies using self-billing on a large scale or working with many subcontractors in Poland.

In some cases, it may be reasonable to:

• introduce approval of the document before it is sent to KSeF,
• reduce reliance on PDF drafts alone as the basis for approval,
• implement an additional control stage before the invoice is submitted to the system,
• clarify responsibilities on both the seller’s and the buyer’s side.

4. Secure the audit trail

In a dispute with the tax authority, it will matter not only how the procedure was described, but also whether the company can prove that it was actually followed. For that reason, it is worth ensuring proper archiving of evidence connected with invoice approval.

In particular, it is advisable to secure:

• email messages relating to approval or comments,
• system logs confirming the document workflow,
• versions of documents presented to the contractor,
• confirmation of approval dates and times,
• internal rules on document retention for audit purposes.

5. Consider applying for an individual tax ruling

If the company operates under a more complex model or uses a procedure that differs from the most conservative approach, it may be worth applying for an individual tax ruling in Poland. This does not eliminate all risk, but it may provide a greater level of protection for the specific factual scenario. This may be particularly justified where self-billing covers a large number of documents, different departments or external entities are involved, or the company uses its own tools to manage the approval workflow.

For businesses that want to organise not only self-billing itself but also the broader workflow of accounting documents and tax settlements, it may be worth considering Customer Invoice Portal by getsix®, which supports the handling of accounting documents, integration with the National e-Invoicing System in Poland (KSeF) and invoice approval management in a more transparent operating model.

Is it worth changing procedures already?

From a business perspective, the answer is yes. At the very least, companies should conduct an audit of their current model. Not every business must immediately implement the same highly formalised XML approval process before submission to the National e-Invoicing System in Poland (KSeF). However, every company using self-billing in Poland should now know whether its current procedure could realistically withstand a tax audit or a dispute over VAT deduction.

In practice, the safest approach today is to assume that self-billing after the rollout of KSeF is no longer a routine area. It is a process that must be aligned legally, tax-wise and organisationally. In companies using an extensive e-invoicing workflow and settling with many contractors, it may be useful to review this area together with a broader assessment of accounting and document processes.

In such situations, Customer Invoice Portal by getsix® may also be worth considering, because it helps structure accounting document workflow, supports integration with KSeF and enables invoice approval to be managed in one place, making it easier to limit procedural risk and prepare the business for the practical challenges of e-invoicing in Poland.

FAQ – frequently asked questions

Self-billing itself remains permissible after the introduction of the mandatory National e-Invoicing System in Poland (KSeF). This follows both from the Polish VAT Act and from the official materials of the Polish Ministry of Finance, which stress that the mechanism has not fundamentally changed with the rollout of the system. The issue is therefore not whether invoices may still be issued by the buyer, but how the approval procedure should be structured correctly.

The KIS ruling of 27 February 2026 shows that the Polish tax authority expects a very strict model: prior approval of the invoice content in XML form, before the invoice is sent to KSeF. That position does not follow clearly from the literal wording of the statute, which is why it raises justified concerns. Even so, it should not be ignored, because in a dispute with the authorities it may be used to challenge the right to deduct VAT.

The most sensible strategy today is to review the contracts, the approval process and the evidence trail. In 2026, the absence of penalties for mistakes in using KSeF should not create a false sense of security, because the risk connected with self-billing may appear not in the technical use of the system itself, but precisely in the area of VAT deduction.

If you have any further questions or require additional information, please contact your business relationship person or use the enquiry form on the HLB Poland website.

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