431

Request Header Fields Too Large

Official
Client error responses (400-499)
The request header is too large

Specification of the HTTP status code 431

The 431 Request Header Fields Too Large status code indicates that the server is unwilling to process the request because its header fields are too large. The request MAY be resubmitted after reducing the size of the request header fields.

It can be used both when the set of request header fields in total is too large, and when a single header field is at fault. In the latter case, the response representation SHOULD specify which header field was too large.

For example:


HTTP/1.1 431 Request Header Fields Too Large Request Header Fields Too Large
Content-Type: text/html

Responses with the 431 Request Header Fields Too Large status code MUST NOT be stored by a cache.

Source / Quote by: The 431 Request Header Fields Too Large HTTP Status Code is specified by section 5 of RFC6585.

How to throw a 431 statuscode with PHP?

To throw the HTTP status code 431 on a web page, the PHP function http_response_code can be used. The syntax is as follows: http_response_code(431) (PHP 5 >= 5.4.0, PHP 7, PHP 8)

Test the 431 HTTP status code

In order to be able to display the HTTP status code (in this case 431 Request Header Fields Too Large) and other information on the client side, the development console must be opened with F12. Afterwards you have to navigate to the tab "Network". Now you can open the page, in the network tab you should see the web page (example index.php). This must be selected and then the Herder section must be selected. Here the user will see the following result:

Status code 431 Request Header Fields Too Large
Overview
URL: https://http-statuscode.com/errorCodeExample.php?code=431
Status: 431 Request Header Fields Too Large
Those: Network
IP address: XX.XX.XX.XX
Status code 431 Request Header Fields Too Large

How to create a custom error page for the 431 status code

Creating your own 431 Request Header Fields Too Large error page is relatively easy with the web server "Apache" as well as with the web server "NGINX".

Apache Webserver

The web server "Apache" is one of the most popular web servers on the Internet. To create an own 431 Request Header Fields Too Large error page in "Apache", the following change must be made in the following file.

File: .htaccess
ErrorDocument 431 /errors/431.html

NGINX Webserver

Similar to the web server "Apache", "NGINX" is also widely used on the Internet. To create your own 431 Request Header Fields Too Large error page in "NGINX", the following change must be made in the following file.

File: sites-enabled/default
error_page 431 /431.html;
location = /431.html {
    root /usr/share/nginx/html;
    internal;
}

Browser compatibility of the 431 status code

Chrome no data
Edge no data
Firefox no data
Opera no data
Safari no data
Chrome Android no data
Firefox for Android no data
Opera Android no data
Safari on iOS no data
Internet no data
WebView Android no data

Constants in programming languages

Microsoft Windows Runtime:
HttpStatusCode.RequestHeaderFieldsTooLarge
Go (Golang):
http.StatusRequestHeaderFieldsTooLarge
Symfony:
Response::HTTP_REQUEST_HEADER_FIELDS_TOO_LARGE
Ruby on Rails:
:request_header_fields_too_large
Author: Tony Brüser
Author: Tony Brüser

Tony Brüser is an enthusiastic web developer with a penchant for HTTP status codes.

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