Cross device messaging

A method comprising:

• storing a user profile, the user profile comprising a presence document indicating active devices associated with the user profile and capabilities of the active devices;
• providing the presence document to a first device that is associated with the user profile, wherein the presence document identifies a second device as a potential relay device;
• receiving, from the first device, a signal comprising a message designating the second device as a relay device to send the message and a third device to receive the message;
• sending, to the second device, the signal comprising the message;
• causing the message to be sent to the third device;
• and
• receiving, from the second device, a synchronization signal comprising a delivered message, the delivered message comprising the message and metadata associated with delivery of the message to the third device.

A device comprising:

• a processor;
• a computer-readable medium having thereon computer-executable instructions, the computer-executable instructions responsive to execution to configure the device to perform operations comprising:
• receiving, at the device based on a determination that the device is a compatible device capable of sending messages via an operator network, a signal comprising a message to be delivered to a recipient device via the operator network, wherein the message originated at an endpoint device that is distinct from the device;
• sending an acknowledgment signal to a user profile, wherein the acknowledgement signal comprises an indication of delivery of the message;
• sending the message to the recipient device via the operator network;
• and
• causing a synchronization of active devices associated with the user profile by sending a synchronization signal comprising a delivered message to the user profile, wherein the delivered message includes data associated with delivery of the message.