<p>Urban vitality is a key driver of human well-being and sustainable development, yet the synergistic impact of the built environment and digital life on vitality remains insufficiently explored. This study analyzes district and county level units in China using multi-source data, including remote sensing and mobile phone application usage. By combining econometric models with qualitative comparative analysis, we examine the interactive effects and conditional configurations of physical and digital factors on urban vitality. Findings reveal that the interaction between the built environment and digital life significantly enhances urban vitality, with notable spatial spillover effects on neighboring regions. The qualitative comparative analysis identifies four pathways to vitality: synergy between built environment and digital life, built environment dominance, digital life deficiency, and built environment deficiency. This research provides a comprehensive framework for understanding how the physical substrate and digital functionality must be coupled to activate urban energy, offering strategic references for spatial planning and digital infrastructure optimization.</p>