This is simple MuleSoft app to expect http call, then return plain ‘hello world’ kind of response. Test run in postman tool.
Main flow:

HTTP Listener set with path ‘/hello’.

HTTP Listener config using localhost and port 8081.

Logger simply log something, to be shown in Console.

Set Payload with “‘Hello MuleSoft!’ ++ ‘ Today is ‘ ++ now()”.
This is string concatenation using ++ operator, and displaying datetime using now() function.

Set the MIME type to ‘text/plain’

Result in postman:

Result in Console:

Keep on learning 🙂
Hello MuleSoft using HTTP Listener, Logger and Set Payload