Abstract: A method for measuring activity across a network of digital wallets utilizing application programming interfaces includes: storing, in a processing server, a plurality of wallet profiles, each profile including data related to an electronic wallet that is not hosted in a computing system including the processing server, the wallet profile including a wallet identifier; receiving a registration message submitted via an application programming interface (API) of the processing server, the message including a new wallet identifier; inserting a new wallet profile that includes the new wallet identifier; receiving transaction notifications via the API, each transaction notification being related to a processed payment transaction and including an associated wallet identifier related to the electronic wallet used to fund the respective processed payment transaction; measuring wallet activity based on a number of unique associated wallet identifiers included in the transaction notifications; and reporting the measur