Google's search advocate, John Mueller, answered a question about whether a CDN can improve rankings in an SEO office hour video, saying that using a CDN for a website doesn't help SEO.
What is a CDN?
Content Delivery Network (CDN) publishes site content to massive acceleration nodes all over the country/world, so that users can obtain the desired content nearby, avoiding network congestion, cross-operator, cross-region, cross-border, etc. It can effectively improve the download speed, reduce the response time, and provide a smooth user experience.
This means that a CDN can significantly improve web page speed.
Do CDNs Help Search Rankings?
People who ask Google want to know if there is a ranking advantage to using a CDN compared to traditional server hosting.
Question: " Does putting a site behind a CDN improve search rankings? Most of the site's traffic comes from a specific country, and the site is hosted on servers located in that country. Would you recommend putting your entire site on a CDN network , to improve page speed for users around the world, or is this not required in our case?"
John Mueller says that using a CDN doesn't help SEO
John Mueller 's answer is clear: " CDNs have no SEO effect."
"Obviously you can do a lot of that.
But I don't think it will have much impact on Google's SEO. "
Google John Mueller
While John Mueller said it wouldn't have a big impact, he added additional clarification:
"The only possible effect I can imagine is what the user ends up seeing.
And, like you mentioned, if most of your users are already seeing a really fast website because your server is there, then you're doing something right.
Of course, if users elsewhere are seeing very slow results because maybe the connection to your country is not very good, then you might have a chance to improve this.
You can see this as an opportunity, if your site is slow for other users then they will rarely go to your site because it is really annoying to go there.
However, if your site is reasonably fast for other users, then at least they have a chance to see a reasonably fast site, which is probably yours.
So from that perspective, if you can do something to improve the overall condition of your site, I think it's a good idea.
I don't think it matters. "
The impact of CDN on search engine crawling
Mueller is back on SEO, this time talking about crawling and the benefits of CDNs.
"As far as SEO is concerned, it doesn't really matter because Google also has to see it soon or something like that.
But it's something you can do to make your website go beyond your current country.
Maybe I should clarify one thing, if Google's crawling is really, really, really slow, then of course that affects how well Google crawls and indexes from the site. "
So this might be an aspect worth looking into.
In most sites I've looked at, I really haven't found this to be a problem for sites that don't have a few million pages.
So, from this perspective, Google's crawl rate in the search console can be double-checked in the search statistics.
If that seems reasonable, don't really worry if it's not super fast. "
A slow or underpowered web server, especially in a shared server environment, may not be able to handle a large number of machine programs crawling, both legitimate and malicious.
This condition on a shared server may cause the server to give up and respond with a 500 server response code because the server cannot respond to all requests.
I've seen this happen with shared servers where the host recommends upgrading to a dedicated or virtual server environment.
A CDN mitigates the effects of a slow shared server by serving web pages from the CDN rather than the server hosting the actual page.
Summarize
Mueller's answer suggests that using a CDN will not have any SEO effect of any kind.
He did say that difficulty crawling a site is not a common problem (except for large sites with "millions of pages").
There are many good reasons to use a CDN, but SEO advantages aren't one of them, Mueller said.
However, domestic search engines such as Baidu say that crawl speed is one of the factors that affects rankings, but there is no news about how much this impact is. Or to put it another way, in the case where speed doesn't affect normal crawl, no effect?
