2.5  International compatibility  Finally, the fifth criterion, international compatibility, states that common standards and rules governing payment systems are needed to promote harmonization and to ensure interoperability of different retail payment methods. 8 In a global economy, fragmented payment system landscape across countries will increase the costs for individual users and societies as whole.
Technical innovations may increase the fragmentation, unless some common ground has been found through open standards. Either in terms of interfaces between systems or in terms of payment systems used. But international compatibility is not only about the interoperability between payment systems. It is also about the compatibility with the laws and regulations of the society around the payment system.