Online platforms and digital marketplaces, such as eBay, Airbnb, Uber, and Amazon, are reshaping industries and transforming how businesses operate and interact with consumers. This course introduces the science behind these online markets, combining key concepts from game theory, economics, machine learning, and algorithms. Students will explore how participants in these marketplaces optimize their strategies and how market designers create rules to ensure desirable outcomes. Students will engage in a mix of problem sets and short projects.