Request Header Fields Too Large

Client Error

The server is unwilling to process the request because header fields are too large

Request headers exceed server limits (often due to large cookies)

How this status code appears in HTTP responses

HTTP Response Header

HTTP/1.1 431 Request Header Fields Too Large

cURL Example

curl -I https://example.com
# Returns: HTTP/1.1 431 Request Header Fields Too Large

This is a client error response indicating the request contains bad syntax or cannot be fulfilled.

Other codes in the same category

The server cannot process the request due to client error

Authentication is required and has failed or has not been provided

Reserved for future use in digital payment systems