MercadoLibre, the largest e-commerce platform in Latin America, plays a dominant role in shaping platform-based commerce across the region. Following this case, the analysis explores two interconnected dimensions: the organizational foundations that structure market interactions in contexts where informal economies prevail—namely, the rules, procedures, and interfaces that define how actors can participate in and challenge the dynamics of the marketplace. The second concerns the governance mechanisms that monitor those interactions.

I argue that platform architecture is designed to solve practical business problems—such as building trust or ensuring user engagement—which in turn shapes how work is directed, evaluated, and disciplined. In this context, platforms can be either restrictive, limiting users' autonomy, or open, allowing users to define the terms of their transactions more freely. This perspective goes beyond two common simplifications: one that sees platforms merely as digital marketplaces connecting different user groups, and another that reduces them to surveillance systems.

Based on qualitative research, including interviews with sellers conducted in 2023, the findings illustrate how these mechanisms operate within MercadoLibre's ecosystem in Argentina. They also reveal the strategies sellers use to retain spaces of autonomy within a highly regulated digital marketplace. This presentation contributes to the platform economy literature by offering a perspective from the Global South, examining how platforms operate within and adapt to informal economic environments.