Mirror site is a page or a copy of a web resource that duplicates its content and is available under a different address. For example, the same website can be opened as https://site.ua and https://www.site.ua. For search engines, these are two different resources, even if the content is identical.
Why is it important to configure the main mirror site? Because it is one of the key steps of SEO optimization. If you do not do this, search engines will automatically choose the main mirror — and it may turn out that the version of the domain being promoted is not the one you intended.
Finding the Primary Website Mirror
For search engines, mirrors are considered duplicate content. As a result, they lower rankings in search results. So it’s important to understand how to find a website mirror.
The first method is to add all versions of the web resource to Google Search Console:
- https://example.com
- http://example.com
- https://www.example.com
- http://www.example.com
Over time, you will see whether they lead to the same site or are indexed separately.
The second method is directly through Google search: first, enter site\:example.com in the search bar, analyze the results, then enter site\:www\.example.com and compare the pages.
Read also: What is a Search Engine Robot and How to Manage It
Proper Merging of Website Mirrors
Indexing the website mirror is essential for search engines. This way, they understand which address should appear in search results. That’s the first point. The second is that having multiple mirrors complicates the promotion of the web resource. When placing external links, you might accidentally specify an alternative URL. The link equity will be divided among different addresses, and the site's actual positions in search results will be lower than expected.
This issue can be avoided by merging the mirrors. With this method, all metrics are combined, and redistribution of link equity becomes irrelevant. And if you don't know how to mirror a site, you just need to follow these steps:
- Set up a 301 redirect in the .htaccess file.
- Install canonical tags. It is enough to add the following to the <head> of each page:
<link rel="canonical" href="https://example.com/this-page-url"> - Add all mirrors to Google Search Console as separate sites. Then, in the settings of each, specify the main address. Search engines will understand which version of the web project is primary, based on redirects and canonical tags.
- Update the sitemap.xml file, adding only canonical URLs.
If you move your website to a new hosting and at the same time change the domain or URL structure, canonicalization (redirect setup) is a required step. It helps search engines transfer all the SEO value of the old site — rankings, backlinks, and traffic — to the new one.
However, if you only change the hosting, without altering the domain or URL structure, no extra actions are needed — search engines will treat it as the same website.
Conclusions
Now you know what a website mirror is and why it is needed. Situations may vary:
- Usually, the need to create a website mirror arises to redirect the address from www to the same address without it.
- Sometimes, when working on backlinks, mistakes are made in setting reverse links. As a result, link equity is split, and this needs to be corrected.
- And sometimes it becomes necessary to abandon an old domain and move the web resource to a new one — while preserving all achievements (rankings, link equity, site structure).
This is common in SEO. A lot can happen during promotion, and drastic measures are often required. But knowledge about website mirrors and how to properly configure them simplifies solving such problems.
