Methods and Devices that provide mechanisms for an air interface capability exchange are disclosed. The air interface capability exchange enables a user equipment device to signal its air interface configuration capabilities to a network device to facilitate software configurable air interface (SoftAI) optimization. The air interface capability exchange involves a UE device signaling information regarding an air interface configuration capability type of the device's air interface. The air interface configuration capability type identifies whether the device supports multiple air interface configurations of the air interface. The UE device may also transmit information regarding air interface configuration options that it supports. The network device may determine a configuration for the UE device's air interface based at least in part on the information provided by the UE device.