406 Not Acceptable

The HTTP 406 Not Acceptable client error response status code indicates that the server could not produce a response matching the list of acceptable values defined in the request's proactive content negotiation headers and that the server was unwilling to supply a default representation.

Proactive content negotiation headers include:

A server may return responses that differ from the request's accept headers. In such cases, a 200 response with a default resource that doesn't match the client's list of acceptable content negotiation values may be preferable to sending a 406 response.

If a server returns a 406, the body of the message should contain the list of available representations for the resource, allowing the user to choose, although no standard way for this is defined.

Status

http

406 Not Acceptable

Examples

Content type not available

The following request assumes that www.example.com/docs/doc1 supports sending a document back as application/rtf:

http

GET /docs/doc1 HTTP/1.1
Host: example.com
Accept: application/rtf;

In this example, the server implementation does not fallback to a default content type like text/html or application/json, but returns a 406 instead:

http

HTTP/1.1 406 Not Acceptable
Date: Wed, 26 Jun 2024 12:00:00 GMT
Server: Apache/2.4.1 (Unix)
Content-Type: application/json

{
  "code": "UnsupportedType",
  "message": "Only 'text/html' or 'application/json' content types supported.",
}

Specifications

Specification
HTTP Semantics # status.406

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406 Not Acceptable

In this article

Status

Examples

Content type not available

Specifications

See also

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