HTTP Status Code

HTTP Status Codes are three-digit codes sent by a Web server in response to an HTTP request from a browser, and indicate whether the request completed successfully or, if not, what type of error occurred.

Some of the most common status codes include 200 (OK), 404 (Not Found), and 500 (Internal Server Error). HTTP Status Codes are important for SEO because it affects the user experience and indexing by search engines, which read standard responses to figure out if a page exists, if it has been moved, if it has been deleted, and therefore should be ignored or removed from the index.

HTTP status codes are divided into five main categories, each identified by a number beginning with a specific digit that indicates the type of response provided by the server. Here are the five categories:

1. 1xx (Informational): These codes indicate an interim response and communicate that information is being transferred. Examples include:
   • 100 Continue
   • 101 Switching Protocols
   • 103 Early Hints
2. 2xx (Success): These codes indicate that the request was successfully received, understood, and accepted. Examples include:
   • 200 OK
   • 201 Created
   • 202 Accepted
   • 204 No Content
3. 3xx (Redirection): These codes indicate that further action is required to complete the request, often in the form of redirection. Examples include:
   • 301 Moved Permanently
   • 302 Found
   • 304 Not Modified
   • 307 Temporary Redirect
   • 308 Permanent Redirect
4. 4xx (Client Error): These codes indicate that there was an error and the request could not be executed due to a problem apparently attributable to the client. Examples include:
   • 400 Bad Request
   • 401 Unauthorized
   • 403 Forbidden
   • 404 Not Found
   • 408 Request Timeout
5. 5xx (Server Error): These codes indicate that the server failed to execute a valid request due to an internal server error. Examples include:
   • 500 Internal Server Error
   • 501 Not Implemented
   • 502 Bad Gateway
   • 503 Service Unavailable
   • 504 Gateway Timeout

Each category represents a different level of communication between the client (e.g., web browser) and the server hosting the requested content. Understanding these codes is essential for Web developers and system administrators to diagnose problems and ensure that Web sites function properly.

Some of the most SEO-relevant and common status codes include:

• 200 OK: The request was successfully executed and the content was sent to the browser.
• 301 Moved Permanently: Indicates a permanent redirect. It is important for SEO as it transfers most of the SEO value to the destination URL.
• 302 Found: Indicates a temporary redirect. Unlike 301, it does not transfer SEO value to the destination URL.
• 404 Not Found: The requested resource was not found. Can negatively affect SEO if the site has many broken links.
• 410 Gone: Similar to 404, but specifies that the resource has been permanently removed.
• 500 Internal Server Error: Indicates a generic server error that prevents the request from executing.
• 503 Service Unavailable: The server is temporarily unable to handle the request, often due to maintenance or overload.