Over the past decade, financial servicesfor the poor have undergone a dramatic transformation. Foryears, financial institutions like banks and microfinanceinstitutions (MFIs) struggled to sustainably serve theworld’s poor. But advances in technology have led toinnovative business models, and with them, new opportunitiesfor expanding the reach of financial services. At the heartof this financial transformation is the rise of digitalpayments services through which nearly any individual orbusiness can send or receive money in real time for almostany purpose and from nearly anywhere in the country, aninclusive payment ecosystem. Overall, the main message thatemerges from a review of both country experiences is thatinteroperability is important, but it is best pursued inmature markets. Engagement with industry is important, andregulators should be cautious when mandatinginteroperability so as not to hinder early investment.Stakeholders need to focus on governance and business rules,as was the case in the year-long negotiations betweenproviders in Tanzania, and not just the technicalimplementation, which is currently the overwhelming focus inGhana. As both markets continue to mature, it will beimportant to monitor the Tanzanian and Ghanaian experiencesin the years to come to fully understand the impact ofinteroperability on DFS.