Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for receiving user input indicating a first user selection of a first form of biometric authentication from a plurality of forms of biometric authentication, providing a first interface for display on a user device, the first interface corresponding to the first form, receiving first biometric data, the first biometric data being provided using the first interface, and selectively enabling communication between the user device and a back-end system based on the first biometric data.