What is a canonical tag?

Why does canonicalization matter?
The problem with URLs
For example, search engine crawlers might be able to reach your homepage in all of the following ways:
- http://www.example.com
- https://www.example.com
- http://example.com
- http://example.com/index.php
- http://example.com/index.php?r...
Modern content material control systems (CMS) and dynamic, code-pushed web sites exacerbate the trouble even more. Many webweb sites routinely upload tags, permit a couple of paths (and URLs) to the equal content material, and upload URL parameters for searches, sorts, foreign money options, etc. You may also have lots of replica URLs to your web website online and now no longer even recognize it.
Canonical tag best practices
1. Canonical links to the current page (= self-referencing) are okay
You can always point your canonical link to the current page, especially if you have other pages that reference to the same page, too. For example, you can have /page-1, /page-2 and /page-3 and each of them can point to /page-1 as canonical target. Often, this is causing some confusion with SEOs.
2. Proactively canonicalize your home-page
3. Monitor your auto-generated canonical links closely
We've seen it more often than we'd like to - bad code can lead to wrong canonical links. This happens mostly with multi-lingual pages or happens trough bugs in the code. We're somewhat experienced in finding these issues and if you are not sure how you can solve these things yourself, feel free to reach out. We're offering low rates for this kind of bugfixing if you send us a nice message. :)
4. Do not create chained linking and send clear signals to the Search Engine
No matter how good Google has become in the past years, if you purposely send out "mixed signals", Google and other Search Engines will have a bad time to correctly follow your canonical links. For example, you should not tell Page A that its canonical link is Page B, then tell Page B that its canonical link is Page C, and tell Page C again that its canonical tag is Page A. This will cause Google to eventually not rank your page at all, causing a loss of ranking for your content all together. Clear instructions for Google will help you to get the most out of your content.
5. Consider "near-duplicate" content carefully
6. Canonicalize cross-domain duplicates
30x Redirects vs Canonical Tags
A main misconception about SEO canonical tags/links and redirects is that they are the same thing when in reality, they are not just technically completely different. A redirect will - as the name states - redirects a request to another location. A canonical link will not cause any redirection of any kind in the browser. Only the Google Bot and such will understand the canonical link, but a redirect will completely move the request to another location. We do that for our Service Pages in our website, for example, as we moved over from static content to dynamically managed content in the backend. We didn't wanted to lose the traffic for the serviced pages, so we created Permanent Redirects. However, we also implemented Canonical Links in these pages, to tell the Search Engines that these pages are "the right ones".
How to check and control your canonical tags for SEO
When trying to check your canonical tags, there is a number of options you have to check if you have the right SEO performance. Here is a little checklist for you:
- does "this" page have a canonical tag?
- does the canonical link point to the desired target page that I want to be ranked?
- are both pages able to be crawled and indexed by my robots?
- Am I disallowing crawling for the page in my robots.txt file?
There are plenty of tools out there that can help you to better understand how your SEO works on your page. For example, we are using Ubersuggest. Its a relatively cheap tool to get the most out of your content.