How to use canonical tags for technical SEO

Canonical tags, also known as “rel canonical,” are a way to tell search engines which version of a webpage should be considered the “original” or “primary” version. Using canonical tags can help improve your website’s technical SEO by preventing issues caused by duplicate content, and by making it clear to search engines which pages you want to have indexed.

Here’s a step-by-step guide on how to use canonical tags for technical SEO:

1. Identify duplicate content: The first step in using canonical tags is to identify any duplicate content on your website. This can include pages with identical or very similar content, as well as pages that are accessible through multiple URLs (for example, example.com and www.example.com).
2. Choose a preferred version: Once you’ve identified duplicate content, you’ll need to choose which version of the page you want to be considered the “original” or “preferred” version. This will typically be the version that has the most incoming links, the highest traffic, or the most complete and up-to-date content.
3. Add the canonical tag: Once you’ve chosen a preferred version of a page, you’ll need to add a canonical tag to the other versions of the page. The canonical tag should be placed in the head section of the HTML code, and should include the URL of the preferred version of the page. The format of the canonical tag should be:

<link rel="canonical" href="https://www.example.com/preferred-page" />

4. Check for any technical issues: Once you’ve added canonical tags to your website, it’s important to check for any technical issues that might be preventing them from being properly read by search engines. For example, make sure that your website’s server is configured to return a 200 HTTP status code when the canonical tag is in place, and that the preferred version of the page is not blocked by your robots.txt file.
5. Monitor your pages: It’s important to monitor your pages with canonical tags to see if they are working properly, you can use webmaster tools or other technical SEO tools to ensure that search engines are indexing your preferred version of the page, and that they are not indexing the non-preferred versions.
6. Consider your Internal linking structure: When you’re setting up canonical tags, it’s important to consider how you’re linking to your pages internally. Make sure that you’re linking to the preferred version of a page whenever possible, and not to any of the non-preferred versions.

Canonical tags are a powerful tool for improving your website’s technical SEO, but it’s important to use them correctly. By identifying duplicate content, choosing a preferred version, adding the canonical tag, checking for technical issues, and monitoring your pages, you can help ensure that your website’s pages are properly indexed by search engines and that your site’s SEO is not negatively impacted by duplicate content.

It is important to note that Canonicals are just one of the many signals search engines use to understand the structure of your website and to serve the right content to users, it will also depend on other factors like backlinks, content, etc. It’s important to have a holistic approach to SEO, canonical tags are just a piece of the puzzle.

In addition to the steps outlined above, there are a few other things to keep in mind when using canonical tags for technical SEO.

7. Use the “self-referencing” canonicals: Whenever possible, you should use “self-referencing” canonical tags. These are tags that point to the current page itself, rather than to another page on your website. This can help search engines understand that the page is the original source of the content, and can also help avoid any confusion that might arise if the preferred version of a page changes in the future. The format of the self-referencing canonical tag is:

<link rel="canonical" href="https://www.example.com/current-page" />

8. Use them in combination with other tags: Canonical tags are not the only way to indicate the preferred version of a page to search engines. Other tags that can be used for this purpose include the “rel=prev” and “rel=next” tags, which are used for pagination, and the “hreflang” tags, which are used to indicate the language and regional targeting of a page. When using these tags in combination with canonical tags, it’s important to make sure that the signals they provide are consistent and do not conflict with each other.
9. Use them in the mobile version: If your website has a mobile version, it is important to use canonical tags there as well. This will help search engines understand that the mobile version of a page should be considered equivalent to the desktop version, and that any links to the mobile version should be treated as if they were links to the desktop version.
10. Be consistent with external links: It is also important to be consistent with the way that you link to your pages externally, i.e. from other sites. Make sure that other sites are linking to the preferred version of your pages, and consider reaching out to site owners to request that they update their links if they are linking to a non-preferred version of a page.

In conclusion, using canonical tags correctly is a crucial step in technical SEO, it is a way to indicate to search engines the preferred version of a web page among duplicate or very similar pages. Identifying duplicate content, choosing a preferred version, and properly implementing the tags can help search engines crawl and index your site more efficiently, avoid confusion and also prevent any potential SEO penalization from duplicate content. Remember that SEO is a holistic process, and canonical tags are just one aspect of it, so make sure that the rest of your site’s technical SEO is up to par and that your content is of high quality and relevant to users.

Another aspect to keep in mind when using canonical tags is how to handle dynamic pages or parameters in the URLs.

11. Dynamic pages: Some websites use dynamic pages that can generate multiple URLs with similar or identical content. These pages can be filtered, searched, paginated, or sorted by different parameters, creating several URLs that can lead to the same content. To avoid duplicate content issues and confusion with search engines, it’s important to add a canonical tag to all of these URLs pointing to the preferred version, in this way you’re indicating that all the URLs are just different ways to access the same content, but only one should be indexed.
12. URL parameters: Another example of dynamic content is when your website uses parameters in the URLs to change the content or layout of a page. These parameters can include things like session IDs, tracking codes, or sorting options, but are not necessary to the content of the page, it can still cause duplication issues. For example, if you have a product page that can be sorted by different options and this option is included in the URL, you’ll have several URLs that lead to the same product page but with a different sorting, it’s important to indicate to search engines which is the preferred URL, including the canonical tag in all the URL variations pointing to the preferred version.
13. Handle cross-domain canonicals: If you have several domains or subdomains that contain similar content, it’s important to use cross-domain canonicals to indicate to search engines the preferred version. This can be done by including a canonical tag in the non-preferred version of the page that points to the preferred version on a different domain or subdomain. This will tell the search engine to index only the preferred version.

Canonical tags can be a powerful tool for resolving duplicate content issues and directing search engines to the preferred version of a page, but it’s important to use them correctly. Handling dynamic pages and URL parameters, and cross-domain canonicals correctly is crucial for proper indexing and avoiding any negative effects on your site’s SEO.

As a reminder, it’s also important to keep in mind that canonical tags are just one part of the puzzle, you should make sure to have a good internal linking structure, high-quality content and a good user experience, and a well-structured site. Following the best practices and guidelines outlined in this article will help you effectively use canonical tags to improve your technical SEO and avoid any potential issues.