<![CDATA[Live-streaming e-commerce has transformed online shopping into a real-time environment characterized by social interaction, interactivity, immersion, and immediate purchasing opportunities. However, limited understanding remains regarding how different social and interactive stimuli influence impulsive buying through affective and cognitive mechanisms, and whether these relationships vary under situational pressure and gender differences. This study examines the effects of streamer social presence, viewer social presence, and interactivity on impulsive buying behavior through flow experience and customer trust within the Stimulus–Organism–Response (S-O-R) framework. A quantitative cross-sectional survey was conducted among Indonesian consumers with prior live-streaming commerce purchase experience. From 335 responses, 293 met the eligibility criteria, and 14 outliers were removed, resulting in 279 valid respondents. Data were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM), including indirect-effect analysis, moderation testing, Measurement Invariance of Composite Models (MICOM), and Multi-Group Analysis (MGA). The results show that streamer and viewer social presence positively influenced flow experience and customer trust, with viewer social presence demonstrating the strongest effect on flow experience (β = 0.404, p < 0.001). Interactivity significantly influenced flow experience (β = 0.152, p = 0.013) and customer trust (β = 0.355, p < 0.001), with a stronger effect on trust. Flow experience (β = 0.342, p < 0.001) and customer trust (β = 0.184, p = 0.013) positively predicted impulsive buying behavior. Time pressure directly influenced impulsive buying (β = 0.312, p < 0.001) but did not moderate the effects of flow experience or customer trust. MGA revealed a significant gender difference only in the flow experience–impulsive buying relationship (Δβ = 0.357, p = 0.013). These findings extend the S-O-R framework by demonstrating distinct affective, cognitive, situational, and social pathways underlying impulsive buying in live-streaming commerce.]]>
