A system and method are described for establishing two-way communication between devices that have a certain set of hardware and/or capabilities allowing the devices to send and receive SMS/MMS messages using cellular networks on behalf of devices that lack the hardware and/or capabilities. A user's device lacking SMS/MMS capabilities queries an identity management service for device capabilities of other devices associated with the same user. The user's device lacking SMS/MMS capabilities can receive from the identity management service a device profile of each device associated with the user. The device profile can include one or more fields, flags, or indicators that specify or are otherwise indicative of hardware and/or software capabilities of a device. The user's device lacking SMS/MMS capabilities can select a device having SMS/MMS capabilities to act as a proxy based on a device's corresponding device profile that indicates that the device has SMS/MMS capabilities.