201 Status Code Explained
A 201 status code indicates that a request was successful and as a result, a resource has been created (for example a new page).
Why it Occurs
The newly created resource can be referenced by the URL(s) returned in the entity of the response, with the most specific URL for the resource given by a Location header field. The response SHOULD include an entity containing a list of resource characteristics and location(s) from which the user or user agent can choose the one most appropriate.A 201 response MAY contain an ETag response header field indicating the current value of the entity tag for the requested variant.
What it means
The entity format is specified by the media type given in the Content-Type header field. The origin server MUST create the resource before returning the 201 status code.