Fly io Newbie: Making internal requests between apps

Look at this nodejs 6pn example: github/fly-apps/privatenet/lookup.js.

Do note that your fly apps would also need to be listening on fly-local-6pn address on whatever 6pn port you intend to connect to.

Quoting from Specify instance-id in fly-replay header - #10 by ignoramous

…forwarding requests over Fly’s 6pn (“internal services” listening on fly-local-6pn or :: or _local_ip.internal Private networking not working - #4 by kurt) to the primary instance at <fly-alloc-id>.vm.appname.internal should work just as well: Send request to a specific VM - #2 by greg

Read also: github/fly-apps/nginx-cluster/readme:discovery.