The Deprecation HTTP response header field is used to signal to consumers of a resource (in the sense of URI) that the resource will be or has been deprecated. Additionally, the deprecation link relation can be used to link to a resource that provides additional information about planned or existing deprecation, and possibly ways in which clients can best manage deprecation.
I don’t really get the purpose of a header like this, who is supposed to check it? It’s not like developers casually check the headers returned by an API every week.
Write them a mail if you see deprecated functions being used by a certain API key, probably much more likely to reach somebody that way.
Also, TIL that the IETF deprecated the
X-
prefix more than 10 years ago. Seems like that one didn’t pan out.Can you elaborate on that? The X- prefix is supposedly only a recommendation, and intended to be used in non-standard, custom, ah-hoc request headers to avoid naming conflicts.
Taken from https://datatracker.ietf.org/doc/html/rfc6648
I still work on software that extendively uses X- headers.
The RFC you linked recommends that no new
X-
prefixed headers should be used.The paragraph you quoted does not say you should use the
X-
prefix, only comments on how it was used.See section 3 for the creation of new parameters: https://datatracker.ietf.org/doc/html/rfc6648#section-3
I wouldn’t worry too much about it. The reason they give is mostly that it is annoying if a
X-
header suddenly becomes standardized and you end up having to supportX-Something
andSomething
. Most likely a non-issue with real custom headers.