Redirects and SEO


A redirect is used to move an Internet address to a different URL. The technical implementation is usually quite straightforward. However, one ought to keep certain details in mind to maintain better rankings with Google & co. and to avoid losing users. This is because redirects are also relevant for search engine optimization.

What are redirects?

Redirects are automatic URL transfers. The user types a specific website into his browser, but because of a redirect he is forwarded to another URL.

There are various reasons why users are redirected:

  • The website has moved to another domain.
  • Maintenance work on the website makes a temporary redirect necessary.
  • Smartphone, iPhone or tablet requests are redirected to special mobile dedicated sites.
  • A website can be called up via various domains (for instance versions with or without a dash).
  • The file structure of the website has changed.

Further reasons for redirects are generally of a more technical nature. For instance the sub-domain WWW. The use of the WWW addition in front of the actual domain has become increasingly rare. However, many users type in the standard “www” in front of every address. Redirects of WWW addresses to URLs without this addition are helpful when trying to avoid duplicate content or difficulties in distinguishing between URL data. The same applies to the redirection of HTTP to HTTPS sites.

Different redirects

A fundamental technical differentiation is also important in terms of SEO. There are essentially two types of redirects.

  • HTTP class 300-status codes are used for HTTP redirects. The user (client) is immediately redirected before a specific page is even delivered.
  • On the other hand, client-sided redirects are carried out with PHP or JavaScript. The requested page is initially called up. This page contains a forwarding code. The redirect only occurs after this forwarding code has been read.

Server-sided redirects, created for permanent use, send back a 300-status code response: “Moved permanently.” Google robots also register this message. However, users are not aware of this technical redirect, unless they take a closer look at the address line of their browser. Without a 301-redirect, the client receives the unpleasant 404-error message: “This page does not exist.” Obviously, this only happens if the page itself has already moved. Apart from that, the user sees the outdated content.

The benefit of HTTP redirection: This redirect has no influence on the ranking. The new page inherits the so-called link juice (the influence of existing backlinks) without any losses, from the old page.

On the other hand, the 302-status code is recommended for temporary redirects: “Moved temporarily.” In this case, the Google robot receives the message that existing data should not be deleted and should remain the same because the redirect is only temporary. The temporary forwarding also has no effect on a Google ranking, unless the redirect proves to be permanent in the course of time.

Client-sided or server-sided redirections?

To prevent the risk of losses, in the past, client-sided redirects were viewed with caution. This was particularly applicable to JavaScript redirections. However, Google has been trying to improve processing of this client-sided scripting language for many years. Significant progress has been made here, not least as a result of the growing impact of JavaScript due to the rise of mobile Internet. Meanwhile, it is therefore no longer unconditionally advised to avoid the use of JavaScript redirects. These redirects sometimes even function without ranking losses.

Google also provides answers in a guideline, stating that, by and large, JavaScript redirections are meanwhile being treated in the same way as server-sided redirects. But it is recommended that this version only be used in exceptional cases, for instance when access to the web server is not available. Furthermore, some search engines are not yet as evolved as Google. As long as this is the case, one ought to play it safe – and this is still best achieved with the 301-status code number.

Redirect to mobile sites or responsive design?

In the days of mobile Internet, every website operator is faced with a basic question of whether to offer a separate page for mobile devices or fully shift to responsive design. Google officially prefers the second option. A website created for responsive design does not need to be forwarded because it responds flexibly to mobile terminals. In addition, a uniform Internet presence for desktops, smartphones and tablets minimizes the risk of duplicate content, because it provides the Google robots with only one source of content analysis.

By relying on responsive design from the very start one also avoids the extra work needed to maintain two versions. A further disadvantage of mobile redirects is that the automatic recognition of the mobile terminal is not always straightforward.

How to make a safe domain move

The change of domain or newly addressing individual pages can be achieved without SEO losses if one follows these two steps:

  1. Inform about the move on the Google Search console.
  2. Create a 301-redirect on the server.

Then you have to wait until Google has registered the new address. This can be easily determined by carrying out a site request on the largest search engine. When this is done, you can, if needed, transfer to client-sided redirects, but you do not necessarily have to. Website operators should allow one or two years before fully relinquishing an old domain, because many users access the page by way of stored bookmarks.

The rule of thumb is therefore: Forward in an SEO friendly way by using the server redirect. Every search engine recognizes the 301-redirect, and it will not lead to any downgrades in the PageRank. Despite the fact that Google has made distinct progress in the interpretation of client-sided redirects, this method continues to be the safest option.



Jan Knupper