This paper explores the relationship between postal development and e-commerce from a global perspective. By analyzing datasets on postal development levels and e-commerce across 122 countries, the study investigates how various aspects of postal services correlate with e-commerce activity. The research employs exploratory statistical methods, including correlation matrices, scatter plots, and partial semi-correlations, to uncover patterns and potential causal links between postal metrics and e-commerce adoption. The findings reveal a strong positive correlation between overall postal development and e-commerce activity. However, the impact of specific postal metrics used in the UPU 2IPD (Reliability, Reach, Relevance, and Resilience) on e-commerce varies across different national contexts. Interestingly, postal Reach emerges as more strongly correlated with e-commerce than Reliability, despite the latter’s inclusion in UNCTAD’s B2C index. Case studies of Kenya and Colombia further illustrate how countries with intermediate postal development levels leverage their postal infrastructure to support e-commerce growth, highlighting the importance of digital innovation and addressing infrastructural challenges. The paper concludes by advocating for a broader reconsideration of how postal services are evaluated in the context of e-commerce. It suggests that new metrics capturing the diversity of delivery models and integration of digital technologies are needed to provide a more accurate assessment of a country’s postal capabilities in supporting e-commerce.