A system comprising: a wireless card reader; and an application configured to execute on a processor of a mobile computing device, the application comprising: instructions for making the mobile computing device communicate wirelessly with the wireless card reader; and instructions for making the mobile computing device communicate with a secure server; wherein the wireless card reader comprises: a chip card reader interface; a contactless card reader interface; a processor for performing actions in accordance with instructions; one or more memory devices for storing instructions and data; a power source; and means for communicating wirelessly with the mobile computing device, wherein the processor of the wireless card reader is configured to process card data received from the contactless card reader interface or the chip card reader interface and communicate the card data to the application executing on the mobile computing device via the means for communicating wirelessly with the mobile computing device, wherein the application executing on the mobile computing device is configured to transmit, for payment processing approval, a transaction to the secure server via the instructions for communicating with the secure server, in response to receiving the card data from the wireless card reader via the instructions for communicating with the wireless card reader, and wherein, upon a card interaction at the chip card reader interface, the processor of the wireless card reader is configured to selectively power the chip card reader interface to communicate the card data and not power the contactless card reader interface. a wireless card reader; and an application configured to execute on a processor of a mobile computing device, the application comprising: instructions for making the mobile computing device communicate wirelessly with the wireless card reader; and instructions for making the mobile computing device communicate with a secure server; instructions for making the mobile computing device communicate wirelessly with the wireless card reader; and instructions for making the mobile computing device communicate with a secure server; wherein the wireless card reader comprises: a chip card reader interface; a contactless card reader interface; a processor for performing actions in accordance with instructions; one or more memory devices for storing instructions and data; a power source; and means for communicating wirelessly with the mobile computing device, a chip card reader interface; a contactless card reader interface; a processor for performing actions in accordance with instructions; one or more memory devices for storing instructions and data; a power source; and means for communicating wirelessly with the mobile computing device, wherein the processor of the wireless card reader is configured to process card data received from the contactless card reader interface or the chip card reader interface and communicate the card data to the application executing on the mobile computing device via the means for communicating wirelessly with the mobile computing device, wherein the application executing on the mobile computing device is configured to transmit, for payment processing approval, a transaction to the secure server via the instructions for communicating with the secure server, in response to receiving the card data from the wireless card reader via the instructions for communicating with the wireless card reader, and wherein, upon a card interaction at the chip card reader interface, the processor of the wireless card reader is configured to selectively power the chip card reader interface to communicate the card data and not power the contactless card reader interface.