What Is Canonical URL?
Canonical URL or rel canonical (also called canonical tag) is an HTML tag that prevents duplicate content creation by instructing the search engine that a specific URL is a copy of an original one. This also helps in identifying the duplicate content appearing across URLs. Canonical tag basically helps the search engine point out which URL needs to appear on SERPs.
Canonical Tag Example
Importance Of Canonicalization
Canonicalization matters, because duplicate content damages the ranking ability of a website.
A canonical tag obliterates any duplicacy impediment available in the process of SEO,
as duplication of content on an enormous quantity affects your overall ranking. Not only that but if the web crawler scans large amounts of duplicate content
on your website, it might absolutely ignore original content.
Uses Of Canonical Tags
URLs work more complexly than we assume, as what we consider to be a URL that directs us to one side, the crawler acknowledges it to be different, even if there is a little difference in the URL. For example, look at these two examples:
Even though the difference between them is petty, the web crawlers will still consider them to be a dual entity and will read the contents under second URLs as duplicates. Today’s CMS may aggravate the problem even more. It can create thousands of duplicates for your website without even regarding your knowledge about it.
Best Practices For Using Canonical Tags
Constantly Canonicalize Your Homepage
Your homepage duplicates more in more ways than any other page of your website. So try to add a canonical tag to your homepage consistently in order to maintain your link equity.
Check Your Canonical Tags
Avoid bad coding it can create a different canonical tag for every version of the URL. You need to confirm the format of your URL to avoid creating mismanagement in the working of the tags.
Avoid Complicated Signals
If you use mixed signals to instruct the search engine, it might interpret it differently. If you want to canonicalize page A, then don’t reference page B. Be clear in your commands or you’ll make the search engines commit a grave mistake.
Be Aware Of What You Canonicalize
Some pages can have an enormous quantity of duplicate content that it makes it hard to find out the original. In this case, the webmasters have to practice extreme caution as not to canonicalize the wrong page.
Sometimes, users own several domains that cater to similar services or products. In this case, they might have websites with similar content across domains that the web crawlers will find duplicates. By using canonical tags, you can maintain link equity and avoid its movement to the non-canonicalized sites.
SEO Best Practices
Some webmasters instruct web crawlers to scan canonical tags that are blocked by robots.txt, or is set to "noindex". This is a mistake harmful to the website. A simple way to avoid similar mistakes is to audit your canonical tags. You can right-click on any browser and choose view page source in order to check whether the canonical tag exists on the page or not.