Marketplace is a third party that brings sellers and buyers together. Carousell is a marketplace application that has a very weak payment system because the payment process takes place between the two parties without being mediated by Carousell. This causes various fraud problems on Carousell and Carousell makes no effort to protect consumer rights. This type of research is a normative-empirical type with secondary data supported by primary data. Primary data was obtained from interviews with 4 consumers in Carousell. The results of the research obtained from interview show that consumers prefer to make payments through other marketplaces because they do not trust sellers who provide their personal accounts, there have been many cases where consumers have experienced fraud from sellers. Basically the payment system from the Carousell application is a direct or withour intermediary transaction between consumers and sellers whose payment mechanism depends on the agreement of both parties such as mobile banking or e�banking. Carousell is based on the principles of trust and security and their philosophy and strategy by implementing different steps in building a strong and holistic trust and security strategy in maintaining a trusted application for use by all buyers and sellers. The policies provided by Carousell to consumers, this is the role and responsibility of Carousell in providing transaction system security to consumers and business people.