This is a PoC using StateFun's remote Java sdk wrapped in Scala 3.0.0-RC2. A very basic tweet-impression counter is implemented.
For lack of a suitable web application framework in Scala 3 at the time of writing, Undertow is used.
The architecture of the system is depicted below:
Statefun is magic. All system integrations and network calls are abstracted and handled by the framework.
The developer simply has to implement a Request => Response function.
That said, this complexity is still lingering around in the form of configuration files.
If this was ever to be used in production I would start by creating a DSL to compose
module.yaml in a typesafe way in Scala.