With my system, I create a UUID for each entry, so I'm guaranteed uniqueness there. The other properties (task name) can be whatever you want. You're right tha

With my system, I create a UUID for each entry, so I'm guaranteed uniqueness there. The other properties (task name) can be whatever you want. You're right that it gets even more tricky if you are doing key=>value pairs and are expecting that the key is something that may not be unique across devices (i.e. two devices using the same website domain as they key would lead to a conflict).