Dagger2, providing Retrofit instances with different APIs same time

You just use the @Inject annotation along with the @Named() annotation, like so:

@Inject @Named("provideRetrofit") Retrofit mRetrofit;
@Inject @Named("provideRetrofit2") Retrofit mRetrofit2;

Or you could even inject the Retrofit services directly:

@Provides @Singleton
public CustomService provideCustomService(@Named("provideRetrofit") Retrofit retrofit) {
    return retrofit.create(CustomService.class);
}