The author proposes the scientific and methodological approach to assess the impact of competitive environment factors on online business, taking into account the specifics of active digital transformation background. The article takes on the issue of the development of a system of metrics for assessing constituents. The research questions focused on the interpretation of the directives for the sustainable development of online business, which is based on the personalized and non-predictable expectations of online buyers according to modern strategic concepts. The author develops the program for online business management and development activities to obtain maximum satisfaction of the changing preferences of online buyers and their online trust. The article represents the formulation of the strategic guidelines for the sustainable development of online business in the digital economy, with the synchronous implementation of the client-centric model, IT innovations, omnichannel distribution of goods, and the creation of value propositions. Keywords: Online Business; Competitive Environment; Online Business Management; Sustainable Development of Online Business; Strategic Guidelines for Sustainable Online Business Development.