Recent rapid growth of online business in Indonesia has encouraged companies to embrace knowledge management system (KMS) that enables them to deliver better services to their sellers and customers. The article examines one of most popular e-marketplace provider, Tokopedia,that helps millions of internet users. E-marketplace is defined as an electronic place that links sellers and buyers. It analysed the use of Amazon Web Service (AWS) as an essential component of KMS to manage people's interactions and flow of information within Seller Centre (SC) department. The SC department is a strategic business division of Tokopedia, with main objective to promote sales, store image and managing needs of customers. The outcome of the study will provide insights into how the cloud-based KMS is used by e-marketplace provider.