I just publicly released the first version of my
web+email+database combined server package that
I have been using myself for a while now for all
the different server based projects I have been
working on.
https://www.robalni.org/server/
I try to keep it as small and simple as possible while still being flexible and containing everything in one package that you need to write server applications. It also has no dependencies except for very common stuff like a standard C library and a Unix-like operating system.