Why Subdomains For Multisite Is A Very Bad Idea

Why Subdomains For Multisite Is A Very Bad Idea

Aaargh… which is better: subdomains vs. subdirectories?! One site says we have to use subdomains for Multisite, and another says, No way, that’s wrong”. What’s a dev supposed to do?

… Or a WordPress user.

… Or an eCommerce business owner.

Will the controversy ever end?

Deciding between subdomains and subdirectories for your Multipress site is a loaded question. We know. We’ve been working through this same issue since we started in 2005.

So let’s settle this debate right here, right now, and once and for all. At least as far as using WordPress Multisite is concerned.

In this post, I’m going to show you that the WordPress multisite subdomain vs subdirectory debate can only end badly for poor old subdomains. In fact, subdomains are gonna get more battered and sucker-punched in this fight than a platter of deep-fried calamari.

Who Thinks A WordPress Multisite Subdomain Network Is A Good Idea?

If you haven’t caught up on this fight yet, on one side of the ring we have WordPress Multisite, a beast of a feature that lets you set up an entire network of WordPress sites or blogs using just one installation.

On the opposite side of the ring, there’s WordPress Multisite Subdomains vs Subdirectories, a two-headed monster locked into a perennial battle with itself for supreme domain-ation. Yeah, I know, crazy right?

Now, here’s the thing…

Web developers and weekend WordPress warriors (and worriers) keep searching online for the definitive answer to questions like:

  • Which is better for setting up WordPress websites, subdomains or subdirectories?
  • Which is better for installing WP Multisite, subdomains or subdirectories?
  • Which is better for website SEO, subdomains or subdirectories?
  • Which is better for [insert anything here], subdomains or subdirectories?

Are you getting the picture now?

The Difference Between a Subdirectory and a Subdomain

If you’re brand new and just walked into the arena looking to smell blood, subdirectories look like this: exampledomain.com/subdirectory, and subdomains look like this: subdomain.exampledomain.com.

In a Multisite installation, you have the choice of setting up sites like this:

Subdomain: site1.exampledomain.comsite2.exampledomain.comsite3.exampledomain.com, etc.

Or like this:

Subdirectory: exampledomain.com/site1exampledomain.com/site2exampledomain.com/site3, etc.

To find out which is the better option for WordPress Multisite, we can turn to the following sources:

  1. The Creator
  2. The Ruler
  3. The Experts
  4. The Truth

Wait, what?

Ask The Creator: Subdomain vs Subdirectory For WordPress Multisite?

Tim Berners Lee invented the World Wide Web and when he was done he said it was good and would be open to everyone.

He sure didn’t see WordPress Multisite coming, did he?

So, he’s no good to referee this fight … next!

Ask The Ruler

Here’s what Google’s Webmaster Trends Analyst John Mueller said in reply to the evergreen question of which is more beneficial for SEO: subdomains or subfolders …

“Google Search is fine with using either subdomains or subdirectories.”

Okay… that’s succinctly put. But really, who cares what Google thinks of your website?

All this does is raise more questions (like “will subdomains increase my AdSense earnings?”) from users who will never ‘crack’ Google’s secret algorithm.

So, let’s ding the bell. Round Three!

Ask The Experts

The great thing about asking experts is that while they may not give us definitive answers, they certainly create neato lists.

Let’s go for a quick couple of rounds with the experts and do a recap of the Pros and Cons of using WordPress Multisite as the undercard, followed by the main event of the Pros and Cons of using subdomains vs subfolders in a WordPress Multisite network.

The Pros Of Using WordPress Multisite

  • You can run a network of sites or blogs with one WordPress installation. This makes it easier to manage and administer multiple sites.
  • You can install themes and plugins once and share these across the network. This makes updating themes and plugins easier and saves time (imagine having to update the same theme and plugins on multiple WordPress installations)
  • You can build a business selling hosted websites for all kinds of uses and charge fees and subscriptions while administering everything from a central location.

When Not To Use WordPress Multisite

  • Managing multiple client sites on a WordPress Multisite installation can be a hassle, especially if they decide later they want to host their site with their own hosting provider, install their own themes or plugins, etc. Unless you’re building a network of sites that will share similar functionality, don’t choose WordPress Multisite to manage very different types of websites.
  • Sites on a Multisite installation cannot have their own separate database or IP addresses. So, don’t use WP Multisite if your sites need separate databases or IP addresses.
  • Some hosting companies don’t provide the necessary server requirements for WordPress Multisite or don’t support Multisite on all plans.  If this is the case where you’re currently hosting and you’re not willing to switch hosting providers, don’t use WP Multisite. Check out our behind-the-scenes account of what it takes to host WordPress Multisite on a serious scale.

For a more in-depth look at the pros and cons of using WordPress Multisite instead of running multiple WordPress installations, read our Ultimate Guide To WordPress Multisite.

When To Use Subdomains

  • Websites on subdomains can have their own design, different plugins, etc.
  • Subdomains keep things on the same domain separate. This can help with branding if you have different products or sell to different regions or want to keep different areas of your business separate (e.g. support.example.com or members.example.com).
  • It doesn’t cost more to add additional subdomains, so you save money on domain names.

The Cons Of Using Subdomains

  • Subdomains are an entirely different website.
  • According to John Mueller, Google may take a little longer to figure out that you’re using subdomains instead of subfolders, so building links to pages in subdomains takes longer and requires more effort.
  • If you don’t have enough content on sites set up on subdomains, you could probably squeeze more juice from your content by keeping it grouped using subdirectories.
  • Some services or tools that charge per website might charge you for each subdomain separately (whereas subdirectories would just be counted as one).
  • Subdomains have limitations and challenges around SSL support. You will most likely be required to purchase a more expensive Wildcard SSL certificate.
  • Subdomains can affect hosting performance and increase security risks (explained further below).

Why You Should Use Subdirectories

  • Subdirectories create a unified feel for all sites hosted under the domain. Everything looks like it is part of the same domain.
  • You don’t have to worry about creating new domains or allowing wildcard domains via your hosting provider.
  • It feels more intuitive for users searching your site. Which do you think users will remember more easily? yoursite.com/support vs support.yoursite.com.
  • It can be easier for site development and marketing, especially if you are not an experienced web developer or internet marketer.

Drawback Of Using Subdirectories

  • None.

Okay, so maybe a teeny, tiny weensy concern regarding using subdirectories would be if –and this is a very long iiiifffff — if a site created on a subfolder matched the slug of a post or page on your main domain.

For example, let’s say you create a site at mysecretfamilyrecipes.com and add a page called “Children Make Nutritious Snacks” with the URL mysecretfamilyrecipes.com/children-make-nutritious-snacks. You then create a Multisite network and allow users to set up their own sites on subdirectories.

Someone comes along and creates a site called “Children Make Nutritious Snacks.” This would then have a URL of mysecretfamilyrecipes.com/children-make-nutritious-snacks.

Yes, that’s a problem.

The Truth Of Why Using Subdomains With Multisite Is A Bad Idea

While SEO experts continue to endlessly debate the benefits of using subdomains vs subdirectories, let me just cut to the chase and get to the painful truth.

Yes, the truth hurts, but you need to hear it, so here it is:

Why would you create a rod for your own back by using subdomains?

According to conventional wisdom, we should use subdomains to keep things separate from the root domain and subfolders to keep related things together.

According to the wisdom of Google’s John Mueller, however …

Google may take a little longer to figure out that you’re using subdomains instead of subfolders, but in the long-term, it makes no difference which one you pick.

If it makes no difference which one you pick, why pick the more difficult option that takes Google longer to figure out?

And if you buy into the “subdomains improve branding” argument, do cool consumers and chilled users really care whether they go to princess.disney.com or disney.com/princess to buy their Frozen merchandise? No … so let it go. Let. It. Go. (Even Disney switched from subdomains to subdirectories.)

You can join discussion groups (or comment, like in the comments down below), and debate the subtleties of WordPress multisite subdomain vs subdirectory SEO benefits ad nauseam. But eventually, everything will boil down to time and money where “management” is time and “security” is money.

WP Multisite Subdomains Require More Management Time

Every subdomain you add to your Multisite network is an entirely different website.

Websites installed on subdomains require more server resources to manage and should be seen as separate businesses.

Managing subdomains on a multisite installation also requires other time-consuming tasks (for example, you’ll need to add each subdomain as a separate website property in Google Search Console).

Let me show you an example of the kind of crazy management involved in running a Multisite network I’m talking about.

Look at Harvard University’s website …

Harvard University Website
Harvard University Website – https://www.harvard.edu.

Universities are a perfect example of sites that can benefit from WordPress multisite. If we take a look at how they have structured their web presence, however, it will make your head spin.

Harvard’s website uses subfolders to send visitors to many of the key sections listed on their home page and keep things grouped together under their main domain. For example:

  • Faculty – harvard.edu/faculty
  • Staff – harvard.edu/staff
  • Students – harvard.edu/students
  • Parents – harvard.edu/parents
  • Visitors – harvard.edu/on-campus/visit-harvard
  • Media – harvard.edu/media-relations

If you explore the University’s sitemap, however, we find that many departments host websites using subdomains:

  • Alumni – alumni.harvard.edu
  • Community – community.harvard.edu
  • College – college.harvard.edu
  • Dental – hsdm.harvard.edu
  • Faculty of Arts & Sciences – fas.harvard.edu
  • Law – law.harvard.edu
  • Library – library.harvard.edu
  • Medical – hms.harvard.edu

Some of Harvard’s museums not only run sites under their own subdomains but some even appear to have subdomains under subdomains. For example:

  • Semitic Museum – semiticmuseum.fas.harvard.edu
  • Fisher Museum At Harvard Forest – harvardforest.fas.harvard.edu

Additionally, some parts of Harvard’s web presence, like its WordPress Multisite Blogs network (blogs.harvard.edu) have sites installed in subdirectories of a subdomain:

  • Harvard Blockchain Lab – blogs.harvard.edu/blockchain
  • Clinical And Pro Bono Programs – blogs.harvard.edu/clinicalprobono
  • Travel Experience – http://blogs.harvard.edu/travelexperience
Harvard University Blogs Section
Harvard University Blogs – http://blogs.harvard.edu.

While the above setup is fine for large organizations and institutions like Harvard and many other universities, can you see how many separate site installations have to be managed? It takes a huge amount of resources to manage this.

If you have anything less than infinite resources available, and either option of using subdomains or subdirectories will get you the same result, wouldn’t you choose the more cost-effective option that is also easier to manage? It would surely hurt your business less, wouldn’t it?

Speaking of ways to avoid getting flogged, let’s take a look at the other main reason why choosing subdomains in a multisite network are a very bad idea.

WP Multisite Subdomains Increase Security Risks

We host millions of sites across our Edublogs, CampusPress, and Enterprise WordPress Multisite Hosting platforms.

Edublogs.org
We host millions of sites on Edublogs… and we should have known better!

Ronnie Burt, who heads up our hosting and education services, says that edublogs.org is an example of a subdomain install and that the team often “regrets doing it this way.”

Here are some of the reasons Ronnie cites for regretting using subdomains on Edublogs and other networks that we host:

  • Subdomains have limitations and challenges around SSL support. One of these challenges is that in order to serve your domain over HTTPS, either a ‘Wildcard’ SSL certificate for your domain or a certificate that covers all domains and subdomains that you plan to use must be uploaded with additional expense. Plus, when domain mapping is introduced, this gets really complicated fast.
  • Subdomains usually see higher legitimate bot and crawler traffic, which can increase load and decrease performance (or require higher hosting plans). *
  • Subdomains, in our experience, can make it harder and more expensive to prevent and mitigate DDOS attacks.
  • Other issues include incompatibility with most cloud WAFs or CDNs (Cloudflare, Sucuri, StackPath, etc.)

* This is because bots and crawlers see each subdomain as a separate WordPress install and may crawl each subdomain simultaneously. So, if they are probing for a bunch of exploits or a credential stuffing attack, they will attempt it again and again for every single subdomain, often in parallel. It’s hard enough for a single WordPress site to handle this kind of a load from bots, but multiply that by 10, 100, or 1000 sites and you will have major problems.

The same is true for web crawlers like Googlebot. These adjust their crawl speed per domain to what your site can handle. But with subdomains, they see each site as different, and so can overwhelm your server resources.

Our CEO, James Farmer also expresses his regret for choosing to use a subdomain for the WPMU DEV site, but those reasons have mostly to do with how unsexy our subdomain URL looks. On this point, it should be noted that you can change WordPress Multisite to subdirectories or subdomains without errors. It’s preferable that you don’t, though, and it’s best if you pick one and then stay with it.

Also, if “sexy” is what you are looking for in your domains, domain mapping can take care of your problems.

The Verdict: Subdomains Are A Very Bad, No Good Idea

Learn from our mistakes. If you plan to set up a WordPress Multisite network and are struggling to choose between using subdomains or subdirectories for your sites, look beyond the SEO arguments, which Google claims is just a moot point anyway.

Pick the option that will cause you less pain and save you time and money managing it all.

And if you still can’t decide, go with the option that looks more sexy.

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Martin Aranovitch
Martin Aranovitch Martin believes that we can all live sustainably in a WordPress-centric digital universe and spends most of his time taking copious notes and creating epic tutorials to prove his theory. Before joining WPMU DEV, Martin authored many WordPress guides and courses for beginners.
Have we convinced you to steer clear of WordPress multisite subdomains? Why? Why not? Share your comments below.