Digital platforms are an organizational form made up of a technological architecture and governance mechanisms for managing autonomous complementors. A platform’s success depends on their engagement in value creation and capture. Prior studies of such engagement have mainly focused on a platform’s governance mechanisms without recognizing their interdependence to its technological architecture. There is therefore a limited understanding of how the interplay between governance and architecture configures platform organizations, and why these configurations produce different levels of complementor engagement. In this paper, our analysis of a 12-year study of a shared platform initiative yields three configurations of platform organizations: vertical, horizontal, and modular. Based on these configurations, we develop propositions that theorize the implications of these organizational forms for complementor engagement. We further propose that these insights, which we derive from a shared platform, are particularly relevant for blockchain-based platforms.