A system and method for interfacing between a financial institution and a cryptocurrency exchange is disclosed. A back-end application programming interface (API) receives a request for a banking transaction from a user in a first amount in fiat money related to a financial institution account a second amount in cryptocurrency funds related to a cryptocurrency exchange account. The API communicates with the financial institution to cause the banking transaction in the first amount to be performed by the financial institution on the account of the user at the financial institution. The API converts the second amount in fiat money to an amount of cryptocurrency funds. The API communicates with the cryptocurrency exchange to cause the banking transaction in the amount of cryptocurrency funds to be performed by the cryptocurrency exchange on the account of the user at the cryptocurrency exchange.