A breakthrough technology associated with Industry 4.0 that allows the connection and sharing of data through the open application programming interface (Open API) has been researched by many banks in Vietnam and preparations are being made to apply it to payment activities and provide innovative financial products and services, welcoming in the Open Banking era. However, many believe this is a new field in terms of both technical and legal factors not only in Vietnam but also in the world, so legal gaps and issues regarding data management and security will pose challenges as banks shift from closed to open measures and seize opportunities. It is necessary to continue to improve policy mechanisms and legal frameworks on information security, customers’ personal data, and cashless payments.