The implementation of the National e-Invoice System (KSeF) as a mandatory model for documenting B2B transactions has not eliminated the circulation of invoices sent in traditional formats (PDF, e-mail) within the business environment. Although the legislator aims for full data structuring, business reality, including technical failures, errors by counterparties, or lack of system readiness among suppliers, creates situations in which the purchaser receives a document outside the central system.
From the perspective of a Chief Financial Officer and accounting teams, a key question arises:
Can a supplier’s technical shortcoming deprive the purchaser of the right to deduct VAT and recognize the expense for corporate income tax purposes (CIT)?
Primacy of Substance Over Form: Lessons from CJEU Case Law
A fundamental principle of the VAT system is the tax neutrality for businesses. Tax authorities often adopt a strict approach, linking the right to deduct VAT to the technical correctness of the document. However, the established jurisprudence of the Court of Justice of the European Union (CJEU) opposes such formalism.
In the landmark judgment in Case C-235/21 (Raiffeisen Leasing), the CJEU stated that even a contract may serve the function of an invoice if it contains data necessary to verify the material conditions for the emergence of a tax liability.
Applying this to KSeF
If a PDF document contains accurate data about the parties, the subject of the transaction, and the tax amount, the absence of structuring in XML format cannot automatically result in the denial of the right to deduct VAT. This judgment is particularly relevant even after the implementation of mandatory KSeF, as it reinforces the argument that for the right to deduct, the decisive factors are primarily the material conditions and the verifiability of the transaction, rather than solely the technical transmission channel of the document.
Since, according to the CJEU, a contract itself can serve as evidence, a fully substantive PDF invoice retains its evidential power, provided that the transaction actually took place.
Gerard Goliasz
Position of the Ministry of Finance and KIS in 2026
An analysis of the “KSeF 2.0” handbook and the latest individual interpretations (e.g., 0114-KDIP1-3.4012.804.2025.1.JG; 0112-KDIL1-3.4012.864.2025.1.KM) shows that the Ministry of Finance and the National Tax Information (KIS) recognize the distinction between the issuer’s obligation and the purchaser’s entitlement. At the same time, they increasingly emphasize the importance of correctly determining the type of document and the moment of its “receipt” for VAT purposes.
Particular attention should be paid to invoices issued according to the structured invoice template and delivered electronically to the purchaser outside KSeF (e.g., as XML, PDF, or visual representation), but not yet transmitted by the seller to the system. Such a document, if issued and received electronically, may be treated as an electronic invoice but is not yet a structured invoice under the law until it is sent to KSeF and receives an identifying number.
- Date of Receipt vs. VAT Deduction Moment: For a “regular” electronic invoice delivered outside KSeF, the date of actual receipt by the purchaser is generally decisive. However, for invoices correctly issued in offline mode or during KSeF downtime, KIS adopts a more formal approach: if the invoice is subsequently sent to KSeF, the date of receipt is, as a rule, considered the moment the KSeF number is assigned, not the earlier date of receipt of the XML, PDF, or visualization file. Only this moment should determine the VAT deduction period, provided other statutory conditions are met.
- Practical Exception: If the issuer, despite the statutory obligation, ultimately does not send such an invoice to KSeF, then, according to KIS guidance, VAT deduction may be considered in the period when the document was actually received outside KSeF or within one of the next three accounting periods.
- Corporate Income Tax (CIT): A formal defect in the invoice concerning KSeF does not interrupt the causal relationship between the expense and the revenue.
Operational Challenge
This approach raises a significant operational issue: upon receiving an XML, PDF, or visualized file, the purchaser often does not know whether the seller will enter the document into KSeF, and if so, when. Therefore, safe VAT accounting today requires not only verification of the document’s content but also implementation of a procedure to determine whether the invoice is considered “actually received” for deduction purposes, or whether the receipt moment, according to KIS, is deferred to the date the KSeF number is assigned.
Due Diligence Protocol: How to Avoid Pitfalls
A purchaser receiving an invoice outside KSeF must demonstrate proactive engagement, which in the event of an audit confirms good faith. Ignoring a PDF invoice may be deemed a failure to fulfill the obligations of a diligent entrepreneur.
Implementing the procedure below minimizes the risk of challenging the accounting, and importantly, establishes the correct VAT deduction period, depending on the type of document and the date of “receipt” for tax purposes:
| Step | Action | Evidential Purpose |
| 1 | Material Verification | Confirm the execution of the transaction and the consistency of data in PDF/XML/visualization with the actual state. |
| 2 | Document Type Classification | Determine the type of document received. This determines whether the VAT deduction depends on the actual receipt date or potentially the KSeF number assignment date. |
| 3 | Communication Archiving | Preserve e-mail or supplier statement explaining the absence of the invoice in KSeF (failure, error). |
| 4 | KSeF Monitoring | Check whether the same document was later submitted to KSeF and when it received an identifying number (mitigate risk of duplicate accounting or recording in the wrong period). |
| 5 | VAT Deduction Period Decision | Document whether VAT is deducted based on the actual receipt date or KSeF number assignment date. |
| 6 | Recordkeeping | Account for the document with status labels such as “outside KSeF,” “awaiting KSeF,” “KSeF number assigned” to reduce the risk of errors or double entries. |
Reference to Latest European Case Law
The right to deduct VAT can be supported by recent European case law. In the judgment of the EU General Court on 11 February 2026, Case T-689/24, I. S.A. v. Director of National Tax Information (KIS), an overly formalistic approach to the VAT deduction moment was challenged. The ruling reinforces the argument that material conditions and the principles of VAT neutrality and proportionality should be paramount.
From a KSeF practice perspective, this does not mean that every invoice received outside the system can automatically be accounted for according to the actual receipt date. However, it provides a significant counterpoint to domestic formalism and reinforces the need to document both the file’s receipt moment and the subsequent handling of the document in KSeF.
Why Analyze Each Invoice?
The greatest risk is not the mere absence of a document in KSeF, but accounting chaos. When the same invoice enters the records first as a PDF and a month later as a structured document, it creates the risk of overstating deductible tax.
According to the latest KIS interpretations, the risk now concerns not only double recording but also recording in the wrong period - especially when a document first reaches the purchaser outside KSeF and is later “completed” by the seller via system submission. Therefore, organizations should implement procedures ensuring that VAT deduction occurs in the correct period, after determining the document type and the relevant receipt date for VAT purposes.
At KR Group, we support clients in designing document workflow procedures that effectively protect against supplier errors. Safe accounting today requires a combination of tax knowledge and technical understanding of reporting systems.
We invite you to contact us for an audit of your KSeF procedures.
