You can share read-only access to a datasource from one device to another. This example will show sharing a datasource using portals, you can also do this from the RPC API, but that is beyond the scope of this note.
Creating a Share Code
First, open the datasource that you would like to share from and find the "Share Data" box. Here, you have the option of entering a user's email address to share directly to them or to generate a share code that can be used once by anyone (including yourself). Without entering an email address, click the "Create Share" button. This will generate a share code for this datasource, copy the code.
Using the Share Code
Next, go to the "Data" page and click "Add Data +". Select that you want to add your datasource "From Shared Data".
Then paste in the share code and select the device you'd like to share the data to.
If you plan on reading this datasource from the device side APIs (HTTP or CoAP), make sure to add an alias to the new datasource.
You now have a one-way share setup. If you need data to be shared in both directions, repeat the process but get a share code from the second device and apply it to the first.