HTTP 406 – Not Acceptable
The server cannot produce a response matching the list of acceptable values in the request headers.
Common use case
Triggered when a client's Accept header requests a content type or language the server simply cannot generate, e.g. asking for XML from a JSON-only API.
Example
HTTP/1.1 406 Not Acceptable
{"error":"Only application/json is supported"}History
Part of HTTP/1.1 (RFC 2068, 1997).
Did you know?
In practice it is rarely returned - most APIs simply ignore an unsupported Accept header and return their default format instead of failing the request.