Rel=canonical: the ultimate guide for begginers

Canonical page
Features of usage
Placement methods
Frequent errors
Canonical and 301 redirects
Conclusion

Duplicate information may be gotten rid of using the rel=”canonical” property. The page mentioned in the attribute is regarded as canonical (main) by search engines. Traffic and number of links are the selection criteria for the main page. Duplicate material has a detrimental impact on a website’s search engine ranking. Only the main page may use the canonical attribute; subpages may not. The URL will be included in the index even if there are no duplicates. John Mueller, a Google contributor, suggests adopting self-referential canonical due to the variations between lowercase and uppercase variants.

Canonical page

The canonical page serves as the main destination for links from other pages. It may be required if you sell things with the same description under many categories and URLs. Since these categories are doublets, advertising effectiveness suffers. The rel=”canonical” attribute is prescribed for them. First of all, the preferred address is defined and specified as canonical on other pages. Search participation is limited to canonical pages; non-canonical pages are not included.

Features of usage

The following situations include the canonical attribute:

The canonical attribute is used in the following situations:

Page duplication. Duplicates can have identical content. The most popular product among various variations is chosen and designated as canonical.
HTTP and HTTPS protocols. Both the safe HTTPS protocol and the outdated HTTP protocol are occasionally used to access the resource. It is necessary to specify canonical in order to avoid issues with the site’s indexing.
Mobile URL. The canonical attribute leading to the desktop version is specifies if a mobile version exists.
The country URL. The website employs variations for the same nation that have different URLs but the same language and information. The chosen page is the canonical one.
Case. If various cases are used, addresses are considered different. To avoid problems, the system should only take into account lower case.

Placement methods

The canonical attribute can be positioned in a number of fundamental ways:

Between <head></head> tags. This is the preferred way to do it. Between the tags, the recommended complete URL is written. To reduce the possibility of mistake, absolute references are used instead of relative ones.
A sitemap. The sitemap can be used to indicate the primary URL. The suggestions are optional, and search engines are not compelled to abide with them.
HTTP header. The HTTP header contains information about the primary address. The technique works with PDF files. It is inappropriate for use in HTML texts.
Plugins Different CMS plugins are used to alter the primary URL. Yoast SEO is a plugin for WordPress.

Frequent errors

To prevent issues, it is essential to utilize the canonical property appropriately.

The main URL shouldn’t result in a 404 error.
Closing the canonical page from indexation is prohibited.
You shouldn’t enter the attribute for the pagination’s initial page.
Attribute is written in the HEAD section alone.
Lower case is appropriate here.
Avoid including multiple canonical pages.
The Sitemap shouldn’t contain non-canonical addresses.
Canonical links that go from the original source to other sites are not accepted.
The search engine disregards the attribute if the pages include various content.

Canonical and 301 redirects

The canonical attribute and the 301 redirect have a distinct difference:

The canonical feature enables you to highlight a single page among several that have the same information. The main page and the other URLs are fully accessible when using the attribute.
A 301 redirect sends users to a new page rather than their previous one. In this instance, the old page is not indexed but the new one is. When the old page is deleted, a 301 redirect is performed.

There are some similarities between the two options: they both move link weight and behavioral characteristics from one page to another (behavior factors are not officially confirmed).

Conclusion

To control duplicate material on a site, use the canonical attribute. Proper use enhances the indexing of the internet resource, which also lessens the detrimental effects of content copied by other portals. If used incorrectly, it can cause problems with the site’s ranking.