As mobile payments gain global prevalence, understanding the factors driving their sustained usage becomes imperative. WeChat Pay, integrated into China’s dominant social platform, provides a distinctive context for examining mobile payment continuance intention. This study extends the Technology Acceptance Model by incorporating trust, network externalities, and application-specific features (red envelopes and interface design) to explore users’ continuance intention toward WeChat Pay. We analyzed 650 valid responses from experienced WeChat Pay users using partial least squares structural equation modeling. The results demonstrated that trust and network externalities significantly shape continuance intention, while red envelopes and interface designs further encourage ongoing use. This study offers a comprehensive integrated framework for understanding the continuance of mobile payments and provides actionable guidance for product development and strategic planning.