No. RPC is not exposed over the internet and it is not safe to expose it to the internet.
Nodes communicate using the P2P protocol. There is no need for another node to directly control another node using the RPC commands.
There are many web-service/app which serves bitcoin. What is their tech prototype ?
As my understanding, they must enter bitcoin network by a node. How do they provide service on internet ? I guess they talk to some bitcoin core node by rest/RPC
by IP address and then expose their service by web interface.
do you know some project that i could refer its code ?
actually this question bothers me a lot for a long time...
Thanks