Remote access to Ionic app over network incl. Database

Hi there.
I have the following challenge.

The situation:
On a tablet runs an ionic app statically served from /www directory with a node express server 0.0.0.0:3000.

There should be the possibility that another client in the same network could access the same codebase (which already works. Access over test.fritz.box:3000)
But it also should have remote access to the same persisted data (actually localStorage) from the other client in the network.
I have no clue to get this to work.

Another database solution?

Any advices for a solution are very much appreciated.
Thanks in advance
Marcus