To which process should I attach Visual Studio Debugger to debug a Kestrel application?

Unfortunately, there is no way to tell right now using the tools provided by Visual Studio or .NET Core. Notice, though, that the community has already requested for this feature here, so you can voice your opinion there.

Currently, the best option is to follow the steps to find out the id of the process given the application's port:

  1. Run netstat -abon | findStr "127.0.0.1:{PORTNUMBER}"
  2. Find the Id of the process returned above, and, for faster lookup, the name will be dotnet.exe

If you feel adventurous, you may want to use something like this PowerShell, which will return directly the port number:

 $string = netstat -abon | findStr "127.0.0.1:{PORTNUMBER}"; $results = $string.split(' '); $results[$results.length - 1]

You can print the pid to the console and use that to select from Ctrl-Alt-P

Console.WriteLine($"Running at pid {System.Diagnostics.Process.GetCurrentProcess().Id}");