Hi Flint,
>> Is it possible to pop up a simple NetTalk web server on-the-fly, to handle a simple GET against localhost from a Windows app?
I'm not 100% sure I understand what you mean by "pop up". If you want a web server, then yes, just start a procedure that contains a web server object, you can open that procedure, and close it whenever you like.
>> The trick is that it needs an ephemeral port, because we could theoretically have many such popup servers running at any given moment, so I want the system to issue the port number to me.
The port number is an expression, so you can put a variable in there, yes.
cheers
Bruce