428 Precondition Required
The HTTP 428 Precondition Required client error response status code indicates that the server requires the request to be conditional.
Typically, a 428 response means that a required precondition header such as If-Match is missing.
When a precondition header does not match the server-side state, the response should be 412 Precondition Failed.
Status
http
428 Precondition Required
Examples
Missing precondition in request
A client has fetched a resource my-document from the server, updated it locally, and then tries to send the updated document back to the server:
http
PUT /docs/my-document HTTP/1.1
Host: example.com
Content-Type: application/json
{
[…]
The server implementation requires that all PUT requests for the specific path or type of documents must be conditional and sends a 428 response:
http
HTTP/1.1 428 Precondition Required
Date: Wed, 26 Jun 2024 12:00:00 GMT
Server: Apache/2.4.1 (Unix)
Content-Type: application/json
{
"code": "MissingPrecondition",
"message": "Updating documents requires a precondition header.",
}
Specifications
| Specification |
|---|
| RFC 6585 # section-3 |
See also
- HTTP response status codes
- HTTP conditional requests
- Conditional headers:
If-Match,If-None-Match,If-Modified-Since,If-Unmodified-Since,If-Range 412