Abstract Three-sided markets, which facilitate interactions between consumers, service providers, and platform operators, have emerged as an important model in the platform economy. This research explores the factors influencing the success and sustainability of these markets, with a focus on Postmates, a key player in the gig economy. Utilizing a qualitative case study approach, the paper analyzes existing literature and company data to examine how Postmates operates and sustains interactions between its users. Key factors identified include platform design, user experience, and the role of network effects, where the platform’s value increases as more users join. The study also highlights the significant impact of three-sided platforms on consumer behavior, with convenience and variety driving customer loyalty. In terms of gig economy dynamics, the research underscores the need for balancing flexibility and income stability for couriers. This study provides practical insights for platform operators, policymakers, and researchers, emphasizing the need for continuous innovation to adapt to evolving market conditions and regulatory frameworks. The findings conclude with recommendations for overcoming challenges in three-sided markets and suggest future research directions, including broader case studies and the integration of primary data. Keywords: Three-Sided Markets, Postmates Case Study, Gig Economy, Network Effects.