Are there any guides on how to write and use ktor ...

# ktor

[Big Chungus]

Are there any guides on how to write and use ktor middleware (if it's even possible)

[David Hernando]

This can be a starting point https://ktor.io/docs/lifecycle.html#applicationcallpipeline

[David Hernando]

you can also take inspiration in already built Features, like DefaultHeaders for example

[Joris PZ]

I recently implemented a route authorization middleware, and wrote a blog explaining my current understanding of Ktor's pipeline design, maybe it can help: https://ximedes.com/2020-09-17/role-based-authorization-in-ktor/