Last year, tech giants Google, Facebook, Microsoft, and Twitter established a partnership called the Data Transfer Project (DTP). This project aimed to make it easier to port data in and out of different online services by means of an open source platform. The Project has now added Apple to list of current contributors.
Most online services allow users to download all of their data to their computer. However, if you wanted that data to live in another service, you'd have to first download your data and then upload it to the new service. DTP tries to take out the middleman and transfer that data directly from one service to another. In Apple's case, it will contribute APIs and authorization mechanisms to allow transfers to and from iCloud.
The way DTP works is fairly straightforward. The members each agree to a standard data model format that are grouped into "Verticals". These Verticals could be something like music, contacts, email, or photos. Each company (or third party) can then develop "adapters" to translate that company's APIs into the data models and vice versa. This is what allows the data to actually migrate from one service to another. Authentication adapters obviously allow users to authenticate to the services they wish to transfer data to and from. Task Management Libraries basically handle all of the background processes like error management, retries, notifications, and other "plumbing".
While Apple's addition is welcome, the project still in the development phase. The official DTP website notes that they are "continually making improvements that might cause things to break occasionally."
So far, the most consumer facing features have allowed Google Takeout and the Facebook Access Your Information tool to work together. There could be new user facing tools coming soon with Google's DTP lead, Jessie Chavez, telling The Verge, "We're really encouraged by the progress the Data Transfer Project has made since we announced it last year, and look forward to rolling out our first user-facing features in the coming months."
Check out the official DTP Github page if you're interested in seeing the code yourself.