404 Not Found

The HTTP 404 Not Found client error response code indicates that a server can not find the requested resource. This response code probably is most famous one due to its frequency to occur in the web. These are often called broken or dead links and lead to link rot.

A 404 status code does not indicate whether this lack is temporary or permanent. If the server knows that this condition is likely to be permanent, a 410 (Gone) should be used instead of a 404 status.

Status

404 Not Found

Custom error pages

Many web sites customize the look of a 404 page to be more helpful to the user and to provide guidance. Apache servers can be configured using an .htaccess file and a code snippet like this one, for example.

ErrorDocument 404 /notfound.html

You can take MDN's 404 page as inspiration.

Specifications

Specification	Title
RFC 7231, section 6.5.4: 404 Not Found	Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

Browser compatibility

See also

• 410

• Wikipedia: HTTP 404