Omnichannel retailers are under intense pressure to harness synergetic management of retail technologies and channels in order to promote customer engagement in the competitive market. Drawing on service-dominant (S-D) logic, we develop a research model to examine how omnichannel integration generates customer engagement through facilitating perceptions of fluency and flow in the shopping experience. We empirically validate the model with a multimethod approach, including an instrument development study to establish the measures of omnichannel integration and a field survey study to validate hypotheses. We find that omnichannel integration has three types: informational integration, transactional integration, and relational integration. These types all positively influence perceived fluency, which further generates customer engagement. Moreover, transactional and relational integration positively influence perceived flow, which ultimately facilitates customer engagement. Our article advances the omnichannel retailing literature by proposing three types of omnichannel integration and developing the S-D logic of customer engagement. Our empirical findings also inform omnichannel retailers about how synergetic technology and channel management in omnichannel integration can be used to promote customer engagement.