public static void Main(string[] args)
{
     var config = new ConfigurationBuilder()
                .AddJsonFile("hosting.json", optional: true)
                .AddCommandLine(args)
                .Build();

     var host = new WebHostBuilder()
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .UseStartup<Startup>()
                .UseConfiguration(config)
                .Build();

     host.Run();
}

public static void Main(string[] args)
{
    BuildWebHost(args).Run();
}

public static IWebHost BuildWebHost(string[] args)
{
    return WebHost.CreateDefaultBuilder(args)
                .ConfigureLogging((context, logging) =>
                {
                    logging.AddSerilog();
                })
                .UseStartup<Startup>()
                .Build();
 }

{
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:5005/",
      "sslPort": 0
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "Robert.Project.Web": {
      "commandName": "Project",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      },
      "applicationUrl": "http://localhost:5006"
    }
  }
}

public static IWebHost BuildWebHost(string[] args)
{
        var config = new ConfigurationBuilder().AddCommandLine(args).Build();

        return WebHost.CreateDefaultBuilder(args)
            .UseConfiguration(config)
            .UseStartup<Startup>()
            .Build();
}