Studia Administracyjne

The aim of this article is to verify the mechanism of the National e-Invoicing System (Krajowy System e-Faktur, KSeF) in terms of its compliance with the principle of neutrality of value added tax and, consequently, the exercise of the taxpayer’s fundamental right, namely the right to deduct VAT. This issue is particularly important due to the fact that the dynamic development of information technologies used by tax administrations leads to a significant change in the context of the functioning of VAT neutrality. The mandatory introduction of KSeF from 2026 does not merely constitute another stage in the digitalization of tax settlements but results in a structural transformation of the relationship between the taxpayer and the state with regard to the exercise of the right to deduct VAT. The main research question is to determine whether the mandatory introduction of KSeF constitutes a restriction on the principle of neutrality permissible under European Union law, in particular in with regard to exercising the right to deduct input tax. The research hypothesis is that the compulsory implementation of KSeF may lead to a restriction on the principle of neutrality by introducing additional technological conditions that affect the effectiveness of exercising the right to deduct VAT. The article develops the concept of technological neutrality of tax law and identifies new threats to VAT neutrality arising from technological risk and the automation of control processes. The conclusions lead to a postulate for interpreting the principle of neutrality in the conditions of digitalization, taking into account the requirements of proportionality, legal certainty, and effective protection of taxpayers’ rights. The analysis allows for the conclusion that, under the operation of KSeF, the overriding character of the substantive conditions for the right to deduct VAT is preserved, and that possible formal or technological deficiencies may not limit the taxpayer’s right, provided that there is no risk of infringement of the fiscal interests of the state. The research was conducted using the dogmatic-legal method, enabling a systematic examination of the provisions of the Goods and Services Tax Act and their interpretation in the context of the principle of neutrality, and the comparative legal approach, enabling comparisons to be made with e-invoicing solutions functioning in other European Union Member States. In addition, an analysis of the case law of the Court of Justice of the European Union was carried out, taking into account judgments shaping the application of the right to deduct input tax in light of formal and technological deficiencies.