What are 301 redirects?

A 301 redirect is a function of a web server that allows for a web page (or other file) to change address. The 301 is the method used to communicate the page has "moved permanently."

The term "301 redirect" is used because web servers send a status code with every request that communicate the results from that request.

You've probably encountered another type of status code situation while browsing the web that you'll be more familiar with: the 404 error page. You'll often encounter a 404 error page when you try to visit a page that doesn't exist. The "404" part is the status code that corresponds to a page "not found" error. So, when you try to visit a page that doesn't exist, a properly functioning web server will return a 404 status code.

Likewise, 301 is the status code to communicate that a page was "moved permanently." In other words, it moved and it's not coming back (vs. a 302 status code that means it was a temporary move).

So when people refer to a "301 redirect," they talking about a page that is permanently moving. After the page has moved, in most cases, the developer needs to go in and add a 301 redirect so that, when someone tries to visit the old URL, they get redirected automatically to the new URL.

The 301 code (vs. a 302 code) also tells search engines, "Hey, this page has moved permanently, here's the new address, update your records." Assuming the new URL is found, the search engines will update the page that is showing up in search results to the new address.

So you're solving 2 major problems with a 301:

  1. How does a user know where You're telling a user's web browser that the page has moved so the browser can automatically redirect them to the new URL.
  2. And you're also telling the search engines that the page has moved, permanently, and that they should update the URL they are showing in search results.

Will 301 redirects hurt SEO?

Implementing a few 301 redirects alone, if done correctly, will not have a negative impact on SEO. However, there is the potential for 301s to hurt SEO because of some side effects of using 301s:

  • You should keep track of redirects and carry them over after a redesign. Because of that, adding redirects adds to this overhead (which is small) of keeping track of them all but, more importantly, increases the likelihood that someone WON'T keep track of them and they'll get thrown out during a future redesign. And that can hurt SEO.
  • Analytics packages track pages by their URLs. So if URLs change, analytics tools (including Google Analytics) will track those old pages as if they were completely new URLs. That makes analyzing performance at the page level before and after a redesign where lots of URLs changed extremely time consuming. You also have to be aware that URLs changed in the first place and account for that when analyzing data. If you DO lose traffic or rankings after a redesign, analyzing data at the page-level is exactly what you'll need to and that'll be much more difficult if URLs changed.
  • All redirects add a page request to the loading of the page. That's because your browser requests the old URL, the server responds and says, "it moved here," and your browser then makes a second request for that new URL. That slows load time and load time has a strong impact on rankings and conversion rate.

Moving a few pages

If a small number of pages are moving and you properly implement a 301 redirect, then you shouldn't notice any impact from that change.

Where people get in trouble is when they change something. For example, if you move a page AND change it's content, then yes you run the risk of that page dropping in search. But the problem isn't the redirect in that case, it's the fact that you changed the content.

It's not advisable to move content and change it at the same time. It makes diagnosing problems difficult and extremely time consuming.

Redesigning / relaunching a website

This is where people get into trouble. When people redesign a site, they often make pretty big content changes IN ADDITION TO changing URLs.

This is always extremely risky. And yes, I'm aware that this is the most common approach to redesigning a website, but that's also why it's sort of become common knowledge that search traffic drops after a redesign, usually with the hope that it recovers, possibly higher than before. But that's not necessary at all. Traffic drops are completely preventable.

This is because when a redesign happens, most people end up changing everything, including:

  1. URLs and site structure
  2. Page content
  3. Page design / layout

All 3 of those items can impact SEO. So by changing everything all at once, you've done 2 things:

  1. You've made it exponentially more difficult to ensure you don't do something that will harm SEO
  2. You've also made it exponentially more difficult to track down exactly what caused the change if SEO performance drops after a redesign

I also realize that doing all this at once is, by far, the dominant approach to redesigning a website. This article alone isn't going to change that.

The solution is to ensure your budget includes the cost to have someone well-versed in this sort of thing consult on the project. It's not cheap, but very few web design companies (even those with SEO on the services list) will include this in their scope.

The cost of inadequate planning can be catastrophic. I consulted on a project after a new site was launched that resulted in a 60% drop in lead flow overnight. Fixing the problem only brought back a small % of that lost lead flow. So if your site relies on SEO for a good chunk of business, it might be expensive, but you should definitely budget for proper planning / mitigation work, OR just don't change everything at once.

TL;DR

  • 301 redirects alone won't hurt SEO
  • But they increase the potential for human error and make it harder to diagnose problems later, so you should minimize their use and ensure they're implemented properly when used
  • If you're moving a few pages and not changing content, you're fine
  • If you're moving pages AND changing content (e.g. for a website redesign) then budget for SEO planning or expect a traffic loss