Modern system management has in its arsenal a number of tools for effective design of enterprise management based on digital technologies and artificial intelligence. The synergy of management subsystems of e-commerce enterprises is able to ensure the formation of the effect of growth of business flexibility to changes in the external environment, optimize business processes and positively influence the behavior of online buyers. The aim of the article is to determine the role of synergistic effects of the management system of e-commerce enterprises in the context of a circular business model. It is hypothesized that the synergistic effects of e-commerce enterprise management should be considered through its analysis as a circular internal system consisting of internal and external subsystems. The circular business model essence of the e-commerce enterprise is substantiated. Conceptual approaches to the content of synergistic management are defined. It is proposed to consider the system management as a circular self-reproducing system that has internal (technological core) and external (organizational superstructure) subsystems. The content of synergistic effects according to the signs of their formation is disclosed. On the basis of a cross-approach to the core and superstructure subsystems, the products of their organic interaction were identified. Through the introduction of technologies based on artificial intelligence (AI) and through a combination with effective management technologies, such products are able to form synergistic effects that will lead to an improvement in the quality of value propositions, an increase in customer trust, and an increase in turnover and profits. It has been proven that the systematic approach to the e-commerce enterprise management is based on the synergistic interaction of external elements (management of human resources, knowledge, information technologies, financial and monetary relations) and internal elements (management of technical protection systems, data protection of customers, personnel, contractors, website, and databases) subsystems. Deepening the scientific analysis of electronic commerce tools is of practical importance for the development of strategically correct management decisions in view of diversification of risks of loss of market position, reduction of sales volumes and weakening of competitive advantages. Conceptualization of the synergistic effects of the system management will improve the processes of analyzing the field of e-commerce at the macro- and mega-economic levels and forecasting the economic growth of the industry