A system for providing pairing between user computing devices, the system comprising: a pairing service ; a first user computing device configured to interact with the pairing service via one or more networks; and a second user computing device configured to interact with the pairing service via one or more networks, wherein the pairing service is configured to: authenticate the first and second user computing devices with a first user service account; pair the first user computing device and the second user computing device based on a determination that the authenticated first and second user computing devices are eligible to be paired; detect that the first user computing device and the second user computing device are in physical proximity to each other; receive an actuation of a first user interface control associated with a first user activity from the first user computing device; and responsive thereto : if the first user computing device is unpaired or not in physical proximity with a paired device, operating the first user computing device as an endpoint associated with the first user activity; and if the first user computing device is paired with and in physical proximity to the second paired computing device, operating the second user computing device as an endpoint associated with the first user activity. a pairing service ; a first user computing device configured to interact with the pairing service via one or more networks; and a second user computing device configured to interact with the pairing service via one or more networks, wherein the pairing service is configured to: authenticate the first and second user computing devices with a first user service account; pair the first user computing device and the second user computing device based on a determination that the authenticated first and second user computing devices are eligible to be paired; detect that the first user computing device and the second user computing device are in physical proximity to each other; receive an actuation of a first user interface control associated with a first user activity from the first user computing device; and responsive thereto : if the first user computing device is unpaired or not in physical proximity with a paired device, operating the first user computing device as an endpoint associated with the first user activity; and if the first user computing device is paired with and in physical proximity to the second paired computing device, operating the second user computing device as an endpoint associated with the first user activity. authenticate the first and second user computing devices with a first user service account; pair the first user computing device and the second user computing device based on a determination that the authenticated first and second user computing devices are eligible to be paired; detect that the first user computing device and the second user computing device are in physical proximity to each other; receive an actuation of a first user interface control associated with a first user activity from the first user computing device; and responsive thereto : if the first user computing device is unpaired or not in physical proximity with a paired device, operating the first user computing device as an endpoint associated with the first user activity; and if the first user computing device is paired with and in physical proximity to the second paired computing device, operating the second user computing device as an endpoint associated with the first user activity. if the first user computing device is unpaired or not in physical proximity with a paired device, operating the first user computing device as an endpoint associated with the first user activity; and if the first user computing device is paired with and in physical proximity to the second paired computing device, operating the second user computing device as an endpoint associated with the first user activity. <EOS>