I consider most web-services - certainly glue code - to be at the "application layer". Of course these definitions are always fuzzy. Which isn't to say Rust is

I consider most web-services - certainly glue code - to be at the "application layer". Of course these definitions are always fuzzy. Which isn't to say Rust is never the right choice for those, it's just a more complicated question that's highly project-specific. Which is why it isn't mainstream there like it is in other places.