Benefits of 301 Redirects for SEO

What’s a better day in the entire year to talk about benefits of 301 Redirects on SEO than on 3/01/2013?

What Are HTTP Headers?
Before we jump into the details, a quick technical primer on HTTP headers is probably useful. On technical jargon, the way Internet works is based upon a “Request and Response” model. All browsers (PC, Tablets, or Mobiles devices) make a Request to the server where the webpage is hosted. Once “authenticated”, the server sends the Response back in the form of a copy of webpage. We simply notice this as – “hey the page loaded”.

What Happens During HTTP Authentication?
After the url is typed and entered on a browser, while we are wondering why the page has not loaded yet, several steps are taking place. An IP address is passed to the server from the requesting browser. The requested URL gets translated to an IP (Internal Protocol) address. The server resolves that IP, and then validates the HTTP (Hyper Text Transfer Protocol) after which it looks for the status of the requested page. This is where HTTP headers come into play. Some of the very common HTTP headers are:

HTTP 200 – All good – OK to send Response back to the browser.
HTTP 404 – Requested resource not found – Page Not Found error, commonly caused by a broken link.
HTTP 500 – Dreaded Server Error – Entire server not found, meaning something bad happened.

HTTP 301 Header
A request is responded with “HTTP 301″ if the server determines the page has moved permanently. It’s like letting your post office know that you have moved and they should forward the mail to a new address. In Request-Response model, you just made a 301 Permanent Redirection request.
Similarly, a request is responded with a “HTTP 302″, if the server determines the page has moved temporarily. Going back to post office example, say, you are heading to Hawaii for 2 weeks vacation and you would want the mails be forwarded to your mom’s house for that time-period, you would be making an equivalent of a 302 Temporary Request.

Benefits of 301 Redirects for SEO From Page Old to New Page

Why is HTTP 301 Redirection Important in SEO (Search Engine Optimization)?
As humans move from place to place, webpages on server often move for various reasons, hence redirection is required.

Before Google-Era, redirections were done “carefree” mainly with 3 options:

- With Meta Redirection – “In 5 seconds you will be redirected to a new page … 5 4 3 2 1″
<meta http-equiv=”refresh” content=”5;URL=’http://new-page-url.com/’” />;

- With JavaScript

- Server side redirection
e.g php code – header(“Location: http://new-page-url.com/page-name”);
or
asp code – response.redirect() or response.transfer()

The problem with all of the above methods was apparent when SEO became important because these methods were not able to tell Google that the page has moved hence search engines should also carry-over the “SEO juice” of the old page to the new page.

How HTTP 301 Redirection Benefits SEO?
Now, we can address the importance of these header messages for Search Engine Optimization(SEO). When a page is moved from an URL “a.html” to” b.html”, we obviously won’t want to lose the rankings of page a.html on Google. When a page is moved, the new page b.html is expected to appear where a.html was appearing on the SERP. HTTP 301 Redirect or HTTP 302 Redirect help us achieve exactly that by preserving the SEO value of the old page and transferring it to the new page. This also includes the link juice established by incoming links as well.

So clearly, the benefit of HTTP 301 Redirect is in preserving the SEO value of the page and transferring those to the new page, so the rank in SERP won’t change.

Sample PHP code such as below hugely benefit SEO with 301 Redirection:

<?
header(“HTTP/1.1 301 moved permanently”);
header( “location: http://www.website.com/new-url” );
?>

When implemented correctly, the new page achieves the SEO juice and link juice of the old page within days or weeks. Keep in mind though, not 100% of the SEO juice would be passing. Not one knows for sure what exactly happens there (may be except Matt Cutts), but probably it is safe to state that about 85% of SEO juice is passed to the new page. The most common mistake developers make is to apply 302 Redirect when 301 Redirection is required. Sometimes developers don’t put the code before generating any html content, and it may not work. So redirection code is normally on the top of the page to comply with HTTP/1.1 specification.

Video of Use Case for 301 Redirects Benefiting SEO by Matt Cutts

Reap Benefits of 301 Redirects for SEO With This Advice
Once an webpage is published, it’s best to not change its url for SEO purposes. However, in the real world, things happen and urls need to be updated; so a savvy internet marketer must build a better SEO friendly keyword rich url and apply “HTTP 301 Redirection” on the old page to the new SEO friendly url. Paying attention to this simple fact will eventually improve the ranking of that url for the given keyword.

Now, you have read 301 blog on 3/01, you might be guessing I’d be publishing 302 blog tomorrow or a blog on 404 in about a month. That sounds fun, doesn’t it? Until then, ciao with this valuable link!

About Ujjwal Bhattarai

Ujjwal is an engineer by education, a programmer by hobby, and an internet marketer by choice. Other than 1 minute chess, and biking, his passion includes SEO, SEM/PPC, CRO, and Web Development. As a lifelong student of Internet Development, he is hopelessly addicted to Internet, and sincerely believes after fire, wheel, and decimal point, internet is the fourth most important invention in the human history. Catch up with him on Twitter at @uj2wal or at his Google+ .

One comment on “Benefits of 301 Redirects for SEO

  1. Really Good explanation …One thumb up for u.

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