Abstract
<jats:p>This paper explores key aspects of seller operations within the Russian marketplace ecosystem, which is conceptualized as a multi-sided digital platform coordinating interactions among suppliers, logistics operators, pickup points, and financial services. The organizational and legal forms of market participants (sole proprietorships, limited liability companies, and self-employed professionals under the Professional Income Tax regime) are analyzed, highlighting the dominant role of the Simplified Taxation System (STS) in seller practices. Particular attention is given to systemic challenges in determining taxable revenue, including the mismatch between platforms’ weekly reporting cycles (using Wildberries as a case study) and statutory tax quarters, the complexities of commission accounting, and the classification of “negative commissions” as additional income. A practical algorithm for accurately allocating transactions across reporting periods is proposed, alongside an examination of how neural network technologies and prompt engineering can automate the processing of large datasets.</jats:p>