SEO of sub-domain

Almost all instances of Discourse I have seen have been sub-domains ( and not sub-directory (

Is there any SEO (search engine optimization) hit with using sub-domain instead of sub-directory?


No, none. All that matters is if you have quality content other sites regularly link to.


Hi Jeff,

That is what I think so too but keep getting conflicting signals. I think Google itself indicated that they don’t penalize companies for putting content on sub-domain, but some experiments in which people moved blogs/forums from sub-directory to sub-domain and saw SEO drops indicate that the reality might be different. Maybe the combined power of having everything in single subdomain may be better than splitting main site and forums in different sub-domains. Some of that information is also dated (few years is a lifetime in on the internet).

Some more insight or comments or citation on the current state would be helpful.



Sometimes people are looking for a “magic button” to press to get good results – but don’t fall for that trap. (And there are plenty of people waiting to sell it to you, too. :money_with_wings:) The best thing to do is focus on generating high quality content that a lot of people visit and link to.

If you haven’t already, sign up for Google Webmaster Tools which provides a lot of direct feedback from Google on how well they are indexing your site.


Subfolder is better in my opinion (if your set up is a main site with forum section) from a purely SEO perspective. Especially if it’s an old established site, not so much if it is an entirely new site. If I were setting that configuration up though, I’d probably put it on a subdomain anyway as it seems cleaner. Makes it easy to put the forum on a separate server if wanted as well.

Each subdomain to some extent, is treated as a separate site. Some trust is passed between them it seems. However, it’s not as much as a subfolder which doesn’t require any transfer of authority.

For example, it wouldn’t make sense for the authority of wordpress, wix, blogspot, tumblr etc. to transfer to sites made by users who haven’t attached a custom domain to their site. i.e. The search engines seemingly can somewhat differentiate between these uses it seems. But I honestly think we often overestimate how intelligent search algos are.

That said, it really seems like Google is having a crusade against UGC content (except Youtube). I rarely get any UGC results for my searches unless I specifically append a site name. Even to the extent of needing to apply ‘’ and still getting minimal results. Lots of friends have started needing to do this as well. Maybe we’re just going crazy though. :crazy_face:

So if that really is true, then subdomain might be better for SEO too. To allow your main site subdomain to not be directly considered UGC.

Some other possible differences:

  • SE updates might affect your subdomains differently - hedged bets between updates.
  • Some or most search engines are limiting the amount of search results from the same site/subdomain. So having separate subdomains may give you more opportunity to rank multiple pages for the same queries.
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Gary Illyes, the guy who handles all of this stuff at Google has said on many occasions that subfolder has no benefit over subdomain. In his keynote at Pubcon 2018 he went to far so say that Google doesn’t care.

Yet still we regularly get posts here from users insisting they need subfolder because they read it somewhere on a blog, or have some anecdotal experience which contradicts expert opinion.

That’s the problem here, even after the experts who manage these systems provide definitive answers, people still believe their opinions matter more.

Add the additional technical burden of running a subfolder install of Discourse, and I’m truly baffled why anyone would do it.

Looking at true SEO signals, subfolder actually risks an SEO penalty. TTFB and page load/rendering is a factor for page rankings. Subfolder installations require an extra proxy step between client and server, which introduces additional latency. Hopefully I don’t need to connect the dots there.


The problem is that subfolder is a wildly more complex and fragile configuration, so any imagined SEO upside is far more than outweighed by the difficulty of setting it up and maintaining it over time.

If subfolder was as easy as subdomain, I’d have no objections, because ultimately it doesn’t matter.

:mega: What matters is whether you produce quality content that people visit and link to.

Everything else is just noise, or people trying to sell you a fake shortcut to success without doing the work of producing great content that people visit and link to. Don’t be fooled!


Why is the sub-folder approach more complex? And more importantly, why is it fragile?

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Because it needs to be proxied, and every URL has to be rewritten.

Discourse is built to run on a dedicated domain.

The more elements and configuration required to run any piece of software, the more fragile it becomes.

Discourse is an application, not a website. There is an inherent technical cost in the above, both in terms of complexity and performance.