This rapid review was looking for experience and lessons for establishing digital payment systems where there are weak banking systems, and particularly areas affected by conflict. The main findings are: considerations must be given to technical infrastructure, for example the need for sufficient ATMs and management information systems; regulation is important and regulators must be given the power to act when required; financial literacy and e-money promotion is required; reaching rural areas continues to be challenging for infrastructure and logistics; interoperability, the ability of information to flow between different systems and platforms, is needed for effective functioning; consumer protection must be considered including consumer data privacy, fraud risk, risk of fund loss if there are bank failures, and the possibility for consumers to make uninformed choices.