IS research has extensively examined the role of trust in client-vendor relationships, as well as the role of governance in information technology (IT) outsourcing, but little research has been carried out on the latest manifestation of outsourcing—namely, microsourcing, i.e., the sourcing of smaller scale projects. To extend the literature on the traditional IT outsourcing literature—a stream that largely focuses on medium-to-large scale offline projects—we investigate how to develop trust and commitment in a triadic microsourcing relationship which includes the microsourcer, the microsourcee, and the microsourcing platform (MP). We draw on transaction cost economics (TCE) to theorize a model specifically adapted to the microsourcing phenomenon to scrutinize the influences of formal contractual mechanisms, relational mechanisms, and third-party mechanisms. Combining data from a matched sample of microsourcers and microsourcees on the leading Chinese MP, Zbj.com, the paper deploys degree-symmetric modeling (DSM) for construct conceptualization, measurement, and data analysis. DSM is consistent with the holistic view used to develop the research model for triadic relationships. Findings confirm that the MP is critical in delivering governance mechanisms to ensure the development of triadic trust and commitment. The results suggest that researchers and practitioners should pay closer attention to triadic trust and commitment building through proper governance mechanisms in the online microsourcing marketplace. We argue that this work could be extended to other online digital platforms that involve multiple transacting parties.