Need general advice from experience about kotlin

I need general advice about kotlin from some whom have a lot of experience in kotlin app developments. I like to ask question regarding best libraries for kotlin app developments, when cross applications are made using kotlin would it really have a native look etc..What Api can be used to connect kotlin back end to a laravel dashboard..i mean admin dashboard. That is for example when a mobile app is made in kotlin what api can be used to connect to laravel in case backend is to be in Laravel