Apologies for the off-topic post, but I just wanted to share a thing from work:
In our iOS apps we have a reporting framework for generating reports and outputting these to various formats.
Recently we got a use case for outputting these reports server side, so instead of reimplementing the report format server side we instead deployed a micro service running Swift instead. 
The necessary changes for playing well with SPM and compiling on Linux were very few - and it was very simple to deploy (using Google’s Cloud Run in our case).
I look very much forward to even more code reuse between our iOS apps and our server!