There is no resource at the path.
> As you note, the current state of that entity is that it does not exist.
A thing which does not exist does not have state. Existence (and even moreso non-existence) isn’t a state, existence is logically presupposed in any description of state.
Then please explain how you can write and I can understand the phrase "A thing which does not exist".
Who said you shouldn't? The shorthand is convenient. But it doesn't mean what other statements with the same shape mean. A thing which isn't doesn't have a state or representation.
Many online REST discussions focus too much on shallow linguistic analogies with verbs/nouns.
If you were doing a static website serving from a file system and said the same thing about a filename as a path component, you'd be seen as mad. But there is no difference when there is an id for a potential employee than a name for a potential file: if no employee/file exists when the server looks for the id/name, the correct result is 404 Not Found.
The id isn't the resource, it's part of the path to the resource (and if it is the resource in that URL, you need a different scheme for when you need to find the employee pointed to by the id and not info about the id.)
The content of the file `/api/v1/employees/100` need to be defined off-band somehow since you cant actually put an employee on disk.
moreover part of REST is that you are not responding with static files by path, but with representations of entities; the question then is whether the entity is the employee or the id.
I agree that `/api/v1/employees/100` is not the best name for the id entity, something like `/api/v1/employee-id-status/100` might be more descriptive.
A GET request to that path should return the current state of the resource at the path. As you note, the current state of that entity is that it does not exist.
Let's look at the spec:
>200 OK - The request has succeeded. The information returned with the response is dependent on the method used in the request, for example:
> GET an entity corresponding to the requested resource is sent in the response;
Did the request succeed?
Yes, we found the current state of the entity so we return 200
What do we return?
"An entity corresponding to the requested resource". In this case however we want to represent an entity that doesn't exist.