Slightly off-topic, but I found this article useful when implementing a REST-API:<p><a href="http:&#x2F;&#x2F;www.vinaysahni.com&#x2F;best-practices-for-a-pragmatic-restful-api" rel="nofollow">http:&#x2F;&#x2F;www.vinaysahni.com&#x2F;best-practices-for-a-pragmatic-res...</a><p>It has a section about status-codes: <a href="http:&#x2F;&#x2F;www.vinaysahni.com&#x2F;best-practices-for-a-pragmatic-restful-api#http-status" rel="nofollow">http:&#x2F;&#x2F;www.vinaysahni.com&#x2F;best-practices-for-a-pragmatic-res...</a>