An SEO Guide To Web URL Canonicalisation

17 Rebecca D'Cunha

What is canonicalisation in SEO?

In SEO, canonicalisation refers to web content that has more than one possible URL.

Why is it important?

In SEO, having multiple URLs for the same web content can cause problems with the search engines. It is best used in SEO to tell the search engine spiders, such as the Googlebot, about your websites’ preferred URL format.

How do canonicalisation problems occur?

Canonicalisation can be overlooked during the development stage. Problems are caused when the search engine spiders see multiple URLs pointing to the same page, as they then need to determine which URL is the most relevant to index.

What effect can this have with your websites’ SEO?

There are a few negative effects that this could have with your websites’ SEO.

  1. You could experience ‘splitting of your site’; whereby your website receives more than one search engine index, which means that the search engine is seeing and indexing two URL addresses for the same content.
  2. You could potentially become flagged as a content copier for having duplicate content.
  3. Your website backlinks and PageRank may be split between the two indexed URLs.

What is the best practice to adopt with SEO Canonicalisation?

You can use any of the following commands for the SEO canonicalisation of your website.

A) Head Tag solution

You can insert the following head tag command to canonicalise your web pages. Insert your preferred URL into the tag and then insert the tag underneath the metatags in your HTML code within the HEAD tag.

<link rel=”canonical” href=”http://www.domain.com”>

View the example below.

B) HTACCESS solution

I. Web Page Redirect

You can insert the following command into your HTACCESS file to redirect your web page URLs to your preferred URL.

Redirect 301 /index.html http://www.domain.com/

Click here to read more on redirects

II. Domain Permanent Redirect

You can redirect multiple URLs to your preferred domain via a domain redirect. You can do this by the following.

Option +FollowSymLinks
RewriteEngine onewritecond % {http_host} ^domain.com [nc]
rewriterule^(.*)$ http://www.domain.com

Best Practise For Canonicalisation

  1. Make sure that the internal links within your website point to exactly the same URL, rather than different URLs with the same content.
  2. If your website runs session IDs, be sure to canonicalise the web pages to your preferred URL.
  3. Make sure to use 301 redirects if you need to canonicalise a URL address or domain. Alternatively, use the canonicalisation head tag in web pages that may automatically generate session IDs on URL addresses.