[jabart]

204 no content is an underused http status. 404 should be monitored as an error, 204 as, well no content available. If a status code has two responsibilities that will be a monitoring issue waiting to happen.

[magicalhippo]

So your suggestion is that if I have a /invoice endpoint, a "GET /invoice/abc123" should return 204 if it's an invalid/non-existing invoice number?

Seems reasonable.