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  • 24.03.2023

Perhaps every SEO specialist, both a beginner and an expert in his field, has heard about the rel canonical tool. The thing is that setting canonicity and pagination is an integral element of search engine optimization of a web site. And it is carried out due to the correct affixing of the tag canonical.

Since search engine algorithms are regularly updated, recommendations for using the rel = "canonical" attribute and pagination settings changed according to that time. In this article we will look at what a canon in SEO is, how and when it is used now, and what errors most often occur when working with this element of search engine optimization.

What is the attribute rel = "canonical" and for what purpose is it used?

Tag canonical in SEO optimization is used to prevent duplicate content. It is registered on any web page in the header of an online resource, among the tags

. Due to this, search bots perceive the page, where rel = "canonical" is registered, as a priority, or, as SEOs say, canonical. It is she who will be displayed in the organic issue, and she will be given the link weight of other web-pages with similar content. Thus, by adding the canonical tag, you will specify the canonical link, which will give the web page priority for indexing. If the site has online pages with identical or similar content available at different URLs, and this is often found in online stores where the pagination of product pages is implemented, the most optimal solution would be to introduce rel = "canonical".

How to use canonical to mark a canonical page?

тег каноникалНайбільш популярним варіантом використання канонікала є вищеописаний спосіб. На веб-сторінці, яку необхідно “запустити” в індекс, між

... head> tags prescribe the full URL, and thus denote the canonical reference. It looks like this:. To reduce the probability of error,

it is recommended to prescribe absolute URLs after the attribute.

In addition, canonical urls can be specified in the technical sitemap. True, the canonical attribute is in fact not a rule for search engines, but a recommendation. Therefore, in the case of registering a website in an xml map, search engine bots are likely to ignore it.

The third option is in HTTP headers. This method is suitable only in cases where there is access to server settings. Implementing it for HTML pages is not the best solution. On the other hand, specifying the canonicity of PDFs via an HTTP header is quite a working option: link ; rel = “canonical”.

Configuring the canonicity of the plugin. For the most popular CMS, plugins have long been developed that help form canonical URLs of any pages. Suppose WordPress uses Yoast SEO for this. In Opencard, canonicity is indicated in the engine options, however, only for product cards in the SEO URL section. In Joomla, version 3 and older canonical is included due to the SEF functionality.

Canonical URLs - when should they be customized?

1. If it is necessary to prevent the occurrence of duplicates:

  • web pages with GET-parameters in URL,

  • UTM-tags,

  • filtering pages,

  • caused by the specifics of the engine.

The canonical SEO tag by specialists in such cases is added on all static pages of the web resource.

2. To eliminate duplication of content. It so happens that similar content is available for indexing at different URLs. As a rule, large online stores "suffer" from this, which contain cards of goods placed in several menus at the same time or similar in series, but having differences in color, size, shape. To solve the problem, it is necessary to place a canonical URL on all pages of the same type on a key, priority web page for indexing.

3. When there is a pagination on the site. At the same time, you need to add "Show all" pages to the catalog, showing all the products of the section, blog articles, etc. at once, if they are added to the web site, then on each page of the SEO pagination, SEO optimizers place a canonical URL to "Show all".

Rules for the formation of canonical pages

Using the canonical tag, follow the recommendations below, and then your manipulations will benefit the site:

  • Avoid chains of canonical urls. Consistency, when page. 1 refers to the non-canonical page. 2, and she points using canonical to the third is false.

  • On a web page, regardless of its purpose, only 1 canonical URL is allowed.

  • The canonical URL should point to a web page located on the same domain as the online resource.

  • The page marked canonical must be present on the site and give the server code 200.

  • When independently searching for canonical web pages, Google prefers to choose options with an https protocol.

When rel="canonical" doesn't work?

This method will not bring the expected effect if you apply it to pages where the content is clearly different. In this case, search engines will ignore the recommendations prescribed in the thesis canonical. Also, linking rel = "canonical" will not work when you need to glue pages with and without www, or http and https versions of an online site. For these cases, a page-by-page 301 redirect is used.

Checking canonical links and errors that occur when working with rel = "canonical"

You can check the canon settings using programs for SEO audit of sites, for example, Screaming Frog. The interface of this software contains a separate Canonical section, which shows the number of pages with and without the canonical tag, as well as those that have canonical URLs.

Канонические URLЯкі помилки найчастіше допускають оптимізатори при використанні rel = “canonical”:

  • Specifying as a canonical reference that is located on a subdomain or has a different domain name.

  • Using "canonical" from page. pagination on the 1st page of the catalog instead of "Show all".

  • The designation of a canonical URL that did not fall into indexing because it was closed by a file or metatag robots, or was outside the PS index for other reasons.

  • The presence of 404 errors in the canonical link, simply put, the canonical leads to a non-existent internet page.

  • Using multiple attributes rel="canonical" in the code of the same page or specifying different canonical URLs.

Google recommends for every page. pagination to place the canon on itself, otherwise, if you specify the canonical 1st web page of a category or blog, indexing the following becomes impossible. When placing several canonical urls in the page code, only the first will be taken into account. As for the implementation of the attribute by different methods, for example, in an XML map and directly on a web page, it is necessary to specify the same canonical URL.

Canon and "Watch all"As we wrote above, one of the popular and affordable options for how to set up pagination in the online store is to generate a "Show all"

page. It is created and then indicated as canonical for other pages. catalog. From the point of view of SEO, pagination configured in this way is considered effective, since Google recommends this method, So, it shows the best result for promotion in this search engine. It is also believed that it is convenient for visitors to watch all products on one page, although this does not always work. For comfortable interaction of users with the site, you need a high speed of loading the web-page "Show all", no more than 3 seconds. Therefore, for online platforms with thousands of products, this method may not be suitable. Also, on some site engines, the "Show All" web page may give errors, so you need to determine in advance the possibility of creating such pages within the CMS you use.

To summarize the above

As practice and experience of SEO optimizers shows, the attribute rel = "canonical" has established itself as a useful and effective tool for promoting web-platforms in the search network. With proper use, it can improve the quality of work of specialists and speed up the indexing of the site, which will have a positive impact on the ranking of the promoted online resource.


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Yurij Finiv

Yurij Finiv

Full stack


Professional Fullstack Developer with extensive experience in website and desktop application development. Proficient in a wide range of tools and technologies, including Bootstrap, Tailwind, HTML5, CSS3, PUG, JavaScript, Alpine.js, jQuery, PHP, MODX, and Node.js. Skilled in website development using Symfony, MODX, and Laravel. Experience: Contributed to the development and translation of MODX3 i...

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