Is everyone using Ktor Client on CommonMain having the same warning?

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See <http://www.slf4j.org/codes.html#StaticLoggerBinder> for further details.

SLF4J is a JVM thing. That warning should only be showed on the JVM variant of your app and can be safely ignored. Or you can add an SLF4J logger implementation like Logback to your jvmMain dependencies to view those logs

ok, thanks