Tributação de softwares: uma análise sobre a incidência de ICMS x ISS no âmbito da decisão do STF no Tema 590 da Repercussão Geral

Abstract

This undergraduate thesis analyzes the taxation of software in Brazil, focusing on the definition of competences between the Tax on the Circulation of Goods and Services (ICMS) and the Tax on Services (ISS). This issue, long marked by intense doctrinal and jurisprudential debate, was consolidated by the judgment of the Federal Supreme Court in Theme 590 of General Repercussion (Direct Actions of Unconstitutionality – ADIs 1.945 and 5.659), which established the incidence of ISS on licensing and assignment of the right to use computer programs, regardless of whether they are standardized or customized. The research adopts a qualitative methodology, based on bibliographic and documentary analysis, covering doctrine, legislation, and relevant case law. It seeks to assess the economic and legal impacts of the decision, especially regarding legal certainty, tax neutrality, and federal balance. The study demonstrates that, although the Supreme Court’s decision has settled the historical dispute between States and Municipalities, practical challenges remain in the taxation of new digital models, such as cloud-based software, Software as a Service (SaaS), and artificial intelligence. Furthermore, it highlights the relevance of the Brazilian Tax Reform (Constitutional Amendment 132/2023 and Complementary Law 214/2025), which established the Goods and Services Tax (IBS) and the Contribution on Goods and Services (CBS), replacing ICMS and ISS, introducing in Brazil a dual VAT system, broad-based and non-cumulative. It is concluded that the uniformization of software taxation represents a fundamental step to reduce litigation, ensure tax neutrality, and strengthen federal cooperation, in line with the transformations of the digital economy