Nairobi, Sept. 14 -- Emerging markets are shifting from being users of global financial infrastructure to its innovators. Countries are building payment systems tailored to local economic realities, and those models are now informing global fintech. Kenya and Jamaica are two instructive examples.

Two regional gateways separated by thousands of miles, they differ in geography and economic structure. Kenya is a major East African economy and a gateway to the region. Jamaica is an island gateway economy in the Caribbean, closely tied to North America, CARICOM, and global diaspora communities.

Yet they share critical commonalities. Both are English-speaking markets integrated into global trade. Both have vibrant entrepreneurial cultures and...