In response to the increasing deployment of brand chatbots in the service sector, this study developed a conceptual framework to examine the psychological processes through which brand chatbots contribute to relationship building efforts. A 2 (interactivity: high vs. low) X 2 (anthropomorphic conversation style: warm vs. competent) between-subject design was conducted in the context of the coffee service business. The levels of interactivity in the chatbots were operationalized by altering the subdimensions of interactivity: modality (i.e., media richness, response latency), message (i.e., interdependency in message exchanges), and source (i.e., customization of content flow). Different linguistic elements (e.g., terms of address, vocabulary, punctuation, emoticons) were used to construct two sets of scripts that emphasized either warmth or competence of the chatbots. Based on the results of the pretests, four brand chatbots via Facebook Messenger were developed using the platform provided by GoSky AI Inc.