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kotlinlang

Hello, guys! What is the exact difference between Kotlinx.rpc and Ktor?

They are work on different levels
Ktor is generic HTTP server and Client implementation
Kotlin.RPC is a library which implements RPC service, so you can define service as interface and it generates code for your during compilation. It uses ktor under the hood (so it able to work with HTTP protocol)

so really what to use depends on what you need, asyncronous RPC server (so to allow real-time interaction between server and client written in Kotlin without additional code), use Kotlin.rpc

If you need general http server/client to work with other clients too, use ktor