I have been developing Lua-heavy embedded products as a freelancer for about 20 years now, including VoIP devices, home automation controllers, industrial routers, digital video recorders, and more. These systems typically consist of a Linux kernel, some libc implementation, the lua interpreter and a few 3d party libs support libs to help building the app. The Lua apps ranges from 30k to 100k lines of code, depending on the application. Some of these devices can be considered 'small' in 2025 terms: 8MB of flash, 64MB of ram. Lua is doing great here.

All of these products are still alive today, actively supported and making my customers good money.

Some things come very natural to Lua: Lua <=> C interfacing is a breeze, and while some modern languages are still struggling to figure out how to do proper async, Lua has been able to do this for decades. The language itself is minimal and simple but surprisingly powerful - a few smart constructs like coroutines, closures and metatables allow for a lot of different paradigms.

For new projects at this scale, I would still choose Lua + C/C++ as my stack. Over the last few years I have been visiting other ecosystems to see what I'm missing out on (Elixir, Rust, Nim), and while I learned to love all of those, I found none of them as powerful, low-friction and flexible as Lua.