I can't import class io.ktor.auth.AuthenticationProvider and other classes for ktor, even if I can run a ktor application. Why is it so? Do I need to reference some other dependency? The whole io.ktor.auth package is not available.

This would be in the ktor-auth dependency artifact I think.

Ok. Thanks, Dico! After reading your message, I googled "ktor artifacts" and I found a list of them here: https://ktor.io/quickstart/artifacts.html

On that note, has anyone seen kotlinx-serialization? It's listed https://ktor.io/servers/features/content-negotiation/serialization-converter.html#artifact-74 but cannot be found here https://ktor.io/quickstart/artifacts.html ?

It's "io.ktor:ktor-serialization:$ktor_version". "kotlinx-serialization" is the standard kotlin serialization plugin. I guess https://ktor.io/quickstart/artifacts.html is not updated: gradle can find that dependency just fine.

I can't seem to install any ContentNegotiation libraries... neither Gson nor kotlinx serialisation or Jackson are working for me.

I'll use them later today or in the next days. I'll update you about my experience.