axum is the tokio-team's web framework — composable, type-safe handlers built on tower middleware. The hello-world is small enough to read in one screen.
The standard library ships a production-quality HTTP server. `http.HandleFunc` registers a function; `http.ListenAndServe` blocks forever serving requests.
Kotlin Ktor Server — JSON API with kotlinx.serialization
Install `ContentNegotiation` + `Json` plugin and you get typed (de)serialization for every route. Decode request bodies into data classes; respond with data classes.