Continuing our “SEO ABCs” series, we’ll cover moving a website to a new domain, or domain gluing—what it is, why it’s necessary, and how to do it efficiently and with maximum benefit for your website.
What is domain gluing?
Slicing is the process of combining multiple domains into a search engine index. After slicing, one domain becomes the primary domain—it is ranked by search engines; the others become mirrors of it and are not included in search results.
A mirror is a copy of a website located at a different URL and/or on a different server. For example, search engines will consider the addresses www.site.com and site.com to be mirrors or duplicates. In this case, domain merging is necessary to determine the primary mirror.
Why merge domains?
“Gluing” plays an important role in SEO: it allows you to identify a primary mirror site and transfer traffic, authority, and link equity from other mirror domains to it. At the same time, the primary domain will be the one ranked in search results.
Most often, gluing is used in the following cases:
- When you need to change your domain name. For example, when renaming a company, you need to move to a new domain.
- When there are duplicate sites located at different URLs.
- When a site is available in search results for a domain with and without the www prefix.
- When you need to install an SSL certificate: the site will be accessible via http and https protocols.
- If a search engine incorrectly identifies the primary mirror, the preferred version of the site may be ranked lower by the search engine and lose rankings.
- When a webmaster purchases a domain name in different domain zones—.ru, .ua, .kz, and others—to reach audiences from different regions.
How to merge domains – setting up a 301 redirect
Before gluing domains, you need to pay attention to the following questions:
1. Determine which mirror will be the primary one. If the webmaster hasn’t pre-selected a priority domain, consider the following:
- When gluing domains, it is preferable to designate the one with the best positions in search results as the primary one.
- If you’re merging domains of different ages, it’s best to choose the “oldest” one as the primary mirror, provided it’s not under sanctions. A sanctioned domain should never be merged, even if it’s not the primary one, as there’s a high risk of the sanctions’ negative effects being transferred to the primary mirror.
- Among several options, you should choose a domain with a good history. You can check the domain’s history using the WebArchive service. You can also use Google Search Console to view notification history and traffic trends. Ideally, there should be no sudden spikes in traffic or violation notifications.
2. Make sure your domain is accessible for crawling and indexing by search engines. You can use Netpeak Spider to determine if your domain is accessible to search engines: check the appropriate parameters to verify.
3. To check your site’s indexing using the webmaster tool, you need to add it to Google Search Console (GSC). If the domain has mirrors, all of them need to be added to the tools provided and their rights verified.
Let’s consider an example: when searching for the website nashsite.ua, the results show the addresses https://nashsite.ua and https://www.nashsite.ua. This indicates that the search engine has indexed the two addresses as separate sites—this is bad for the site, as such indexing could degrade its performance.
In our example, we’ll select nashsite.ua as the primary domain and link the mirror to it. To do this, we’ll set up a 301 redirect to the main mirror page.
To set up a server-side redirect, you need to add the redirect information to the .htaccess file for www.nashsite.ua. In our example, the redirect code would look like this:
In this case, we are setting up a 301 redirect from one mirror to the main domain: from www.nashsite.ua to nashsite.ua.
If the site has several mirrors, these steps must be repeated on each of them.
When creating a redirect map, you need to consider the following:
- If the structure of the sites to be merged is the same, a 301 redirect is configured from the pages of the mirror domain to the identical pages of the main one.
- If the mirror structure is slightly different, you need to set up 301 redirects to similar pages.
- If two domains have different structures, you need to set up a redirect from all old pages that are not in the new structure to the main page of the primary domain.
How to add a main mirror to Google Search Console
To merge domains, you need to add mirrors to one GSC and YAV account and confirm your rights to each of them.
Google Search Console
With the release of the new version of Google Search Console, it has become impossible to determine the main mirror within a single domain in the webmaster tool.
The existing “Change Address” tool allows you to move a website from one domain to another, for example, change the domain site.com to site.org or site2.com.
Important: According to Google Search Help, this tool is not used in the following situations:
- transferring a resource from http to https;
- transfer from a www subdomain to a non-www version within the same domain;
- transferring individual pages from one section of the site to another;
- moving a website without changing the URL (when the website URL remains the same, but the hosting providers or CDN have changed).
Therefore, to determine the primary mirror in such cases, it is necessary to use the aforementioned 301 redirect. When merging domains with and without www, Google suggests setting up a canonical tag.
How to check domain gluing
There are several ways to check the correctness of domain gluing, namely whether the main domain is defined.
The easiest way to find out if a site’s main mirror has been identified is to enter the operator “site: new site domain” in the search bar. If no other domains appear in the results, then the main mirror has been identified.
The image shows that the main mirror is on https and without www.
You can check domain gluing using the Redirect Path plugin, which will show the 301 redirect settings.
If all settings are correct, any non-primary domain address will be redirected to the primary domain.
The most reliable way to check domain merging is to look at the metrics dynamics in Google Search Console. If non-primary domains continue to receive impressions and clicks, these domains are not “merged” to the main mirror.
If after gluing the impressions and clicks are equal to zero, then everything is configured correctly.
Common mistakes when gluing domains
There are several typical mistakes when gluing domains:
- The domains that need to be merged have different content. An important requirement when merging mirrors is ensuring that the content is as similar as possible.
- One of the domains is blocked from indexing. To verify that the domain is available for indexing, you can view the indexing report in Google Search Console.
- Incorrect 301 redirect setup:
- redirects are set to an irrelevant page;
- All mirror pages are redirected to the main page of the main domain, while the main domain structure contains relevant pages.
Remember
- The website should be accessible only at one address. If the site can be accessed at different addresses without redirecting to the main mirror site—www.site.ua, site.ua, site.ua/—the situation should be corrected by merging the domains. This will avoid significant traffic loss.
- Properly configured linking allows you to transfer all the “belly meters”—metrics—from mirrors to the main domain, which will be ranked in search results.
- To merge domains, you need to:
- set up 301 redirect;
- Add mirrors to one Google Search Console account and verify rights to each of them.
- The correctness of the gluing must be checked in one of the following ways:
- by entering “site: new website domain” into the search bar and analyzing the results;
- using the Redirect Path plugin;
- track the dynamics of indicators in Google Search Console.
Source: Netpeak
