[inanutshellus]

I recalled there was a "not found" response and used it whilst spitballing the response above, but you're absolutely correct. 400 (Bad Request) and 421 (Misdirected Request), or even 409 (Conflict) -- as another poster mentioned -- would be great responses in that scenario

The main "issue" is that 404 is the normalized response for web servers when an endpoint doesn't exist. So it feels like one is breaking the established paradigm by using something else, but I think it's absolutely worth doing.

Certainly a bigger fan of defaulting to returning a 409 than making my API consumers parse all my response bodies.