This page is part of the Node403 documentation and explains the HTTP 404 Not Found status code used in web servers and APIs.
The HTTP 404 Not Found status code indicates that the server cannot locate the requested resource. The server itself is reachable and operational, but the requested URL does not match any available content.
This response typically occurs when a page has been removed, renamed, or when a client attempts to access an incorrect or outdated URL.
HTTP/1.1 404 Not Found Content-Type: text/html Content-Length: 512
Web servers often display a default error page when a resource cannot be found, although most modern applications implement custom 404 pages to guide users back to valid content.
Proper logging and monitoring help developers identify which URLs generate frequent 404 responses and whether they result from broken links or user navigation errors.
Search engines rely on the 404 Not Found response to detect invalid or removed pages. Returning a correct 404 status code helps search engines remove outdated URLs from their index.
Websites often provide a helpful custom 404 page that allows users to navigate back to valid sections of the site rather than leaving the visitor with a blank error message.
The HTTP 404 Not Found status code indicates that a requested resource cannot be located on the server. It is one of the most common HTTP responses encountered during normal web browsing and application development.
Understanding the causes of 404 responses helps developers maintain clean URL structures and detect broken links within web applications.