I'm toying around with this idea myself. After some thoughts I created a simple node.js app that provides services like a http server and a spotify api client to module that are autoloaded from some folder.
Whenever I feel like it I can very easily extend this platform by just writing a new javascript file. Currently there are thinks like
* An endpoint to show my currently playing track on spotify
* An endpoint that renders one of my todoist lists as html (my whislist)
* A reporting module that receives webhooks from different backup scripts and sends me a report by mail every day
* Move new songs from a spotify playlist to an archive playlist after a few weeks to keep the playlist "fresh"
I always wanted to create a bigger project based on my learnings but I'm not yet completely happy with the technical implementation