Methods, systems, and apparatus are described for storing and transferring application data between devices. In one aspect, a method includes receiving, by a first service running on a first device, from a second service running on a second device, application data for a first set of applications on the second device; causing, by the first service and for each application in the first set, the first device to store the application data for the application; receiving, by the first service and from a third service running on a third device, a request for application data for a second set of applications on the third device; determining, by the first service, that the first device stores application data for the second set of applications; and causing, by the first service, the first device to provide stored application data to the third service running on the third device.