HTTP (HyperText Transfer Protocol) or response status codes refer to requests to a web server made by search engines or visitors on a website.

These codes are always represented by three numbers beginning with 1.2.3.4 or 5. This code indicates the status of a web element.
From 100s to 500s, status code are split within the following categories:

  • 100s: informational. The request has been received and the process is going on.
  • 200s: success: the request has been received and works well.
  • 300s: redirection: the request has been received but needs a extra step to be completed.
  • 400s: client error: the request has been asked by a client but the destination page is not correct.
  • 500s: server error: the request asked by the client was correct but the server failed to deliver it.

And then, even if a lot of different HTTP status code can occur, not all of them impact negatively your SEO.

Which HTTP status code impact your SEO?

200 OK

The request has been successful, which mean everything is normal.

301 Moved Permanently

The requested page has been assigned a new permanent URL so it means any reference to this source should use a returned URL. This redirection is used when an URL needs to redirect to another.

302 Found

This status code means that the server is responding to a request with a page from a different location while the requester keeps using the original location for future request. In clear, this process is not optimal because it doesn’t tell in the right way search engines that a page has changed location. In fact, using this status code obliges search engines to use the redirect as temporary without giving the link juice of 301 redirects.

404 File Not Found

This status means that the server has not find anything related to the requested URL, which can be permanent or temporary. In most cases, a 404 errors message is displayed by webmasters.

410 Gone

As a permanent condition, the URL requested is not available anymore and no forwarding address is known.

503 Service Unavailable

The request asked cannot be realised because of server issues due to overloading or maintenance. This status code should be used whenever the server is out of use for a temporary period. Also, this status code tells search engines to come back later because the page is just out of use for a short amount of time.