{{HTTPSidebar}}
The HTTP 412
Precondition Failed
client error response code indicates that access to the target resource has been denied. This happens with conditional requests on methods other than {{HTTPMethod("GET")}} or {{HTTPMethod("HEAD")}} when the condition defined by the {{HTTPHeader("If-Unmodified-Since")}} or {{HTTPHeader("If-None-Match")}} headers is not fulfilled. In that case, the request, usually an upload or a modification of a resource, cannot be made and this error response is sent back.
Status
412 Precondition Failed
Specifications
Specification | Title |
---|---|
{{RFC("7232", "412 Precondition Failed" , "4.2")}} | Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
{{Compat}}
See also
- {{HTTPStatus("304")}}
- {{HTTPHeader("If-Unmodified-Since")}}
- {{HTTPHeader("If-None-Match")}}