431 Request Header Fields Too Large
The HTTP431 Request Header Fields Too Largeclient error response status code indicates that the server refuses to process the request because the request'sHTTP headers are too long.The request may be resubmitted after reducing the size of the request headers.
431 can be used when the total size of request headers is too large or when a single header field is too large.To help clients running into this error, indicate which of the two is the problem in the response body and, ideally, say which headers are too large.This lets people attempt to fix the problem, such as by clearing cookies.
Servers will often produce this status if:
Status
431 Request Header Fields Too LargeExamples
Header field too large
In the following example, theCookie header is too large in the request:
GET /doc HTTP/1.1Host: example.comCookie: cookie1=value1; cookie2=value2; cookie3=[…]The server responds with a message indicating which header was problematic:
HTTP/1.1 431 Request Header Fields Too LargeContent-Type: text/html<!doctype html> <head> <title>Request Header Fields Too Large</title> </head> <body> <h1>Request Header Fields Too Large</h1> <p>The "Cookie" header was too large.</p> </body></html>Specifications
| Specification |
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| RFC 6585 # section-5 |