iOS: Share settings across different apps on different devices

Question

My goal: Synchronize settings between two different of my apps on two different devices of the user.

From what I can tell, I can

• use App Groups to share settings between different apps on the same device or
• use iCloud to share settings of the same app across different devices.

Is there an easy way to achieve both?

I am aware that I could use iCloud Documents and probably store the settings as a document in iCloud. However, I don't want the user to be able to change those settings externally, which would be possible with iCloud Documents, I assume.

Answer 1

If user have Keychain enabled on devices, you can store data in it and it will be synced across all devices which use same keychain (in most cases they linked to user's iCloud account)