There is a framework for OCaml for this: https://mirage.io/
So if you are interested in learning OCaml and want a unikernel, this would be a possible path to take.
I create cronjobs which run ratt regularly and save the xml to a file in a directory to be served as file by a web server.
After that i can just subscribe to it with my feedreader.
Maybe i will try to use it as a building block for a webservice, but for now i am still figuring out how to write good config files.