I'm using ktor on android and using it over a Wifi connection works fine but over mobile data a simple GET request returning json takes 10+ seconds (I measured 10mbit/s). Is that somehow my fault?

I used ktor in many android apps with the okhttp engine, I never had that kind of issues

If you use OkHttp client or HttpURLConnection do you get a different result?

Same issue with raw Okhttp, but I see I only have to problem on app-startup after that, everything is smooth