Curve is a financial technology company that provides a platform for managing multiple bank cards and accounts in one app. Users can link their various cards to the Curve card, allowing them to make payments while choosing which card to charge after the transaction. This feature helps users keep track of their spending and simplifies their financial management. The Curve app also offers additional benefits, such as cashback rewards and the ability to switch payments between cards retroactively. This flexibility makes it easier for users to optimize their finances and take advantage of different card benefits without carrying multiple physical cards.