Instead of busybox+Lua, I just use TurboLua:
https://turbo.readthedocs.io/en/latest/
Event driven, fast, all the networking basics in place including http, mustache templates and encryption, light and small executable, very nice for embedded applications, signals and fd handling built-in, very easy to use…
Have used it very successfully for million-dollar projects, including some scientific applications running on limited-resource systems (512 megs of RAM) ..
Was very, very easy to add C functions to interface with the web front-end, libffi is great for this purpose, but its also very easy to extend as a standard, well-written Lua/C application ..
This is exactly the sort of thing I'm really interested in. I'm particularly excited about various takes on Lua+batteries, have looked into designing my own (C wrapper with bindings to networking, JSON, templating, and DB libraries), but found Redbean to be almost ideal so never got past overall design to dig into code.
Turbo looks fantastic, though! It's precisely the niche I was looking to have filled, so I'll build a prototype or two in it to see what I think. Very much appreciate the pointer!