Duplicate pages without canonical issue means that website has pages with identical contents without the link tag with the rel=canonical attribute value.
The importance of the issue
Duplicated content degrades the pages’ value, leading to degrading text relevance and making the search engine waste crawling budget and choose the best page among two identical ones. This may lead to the ranking decrease of the main landing page, as well as to negative user experience in case one gets to the duplicate page instead of the main one.
How to check the issue
Using any browser is enough to check the issue. Open the source code of the flawed page To do this, click the right mouse button at any spot of the page and choose “browse the code” option, or apply an online tool https://codebeautify.org/source-code-viewer.
Find the <link> tag with the rel=canonical attribute value. If there is no tag with the attribute, or it forwards to the URL of a current affected page, then there is an issue.
A classic example is when goods are sorted in the page with the help of URL parameters.
main page: https://site.com/asus/
sorting page: https://site.com/asus/?sort=desc
There is an issue, if:
- the page https://site.com/asus/?sort=desc has no link tag formatted as follows: <link rel=”canonical” href=”https://site.com/asus/”>;
- the page contains a link tag forwarding to the current page <link rel=”canonical” href=”https://site.com/asus/?sort=desc”>.
How to fix this issue
To fix the issue, it is necessary to define the main page and specify it in the href attribute of a link tag.
<link rel=”canonical” href=””>
Google recommendations https://developers.google.com/search/docs/advanced/crawling/consolidate-duplicate-urls?hl=en.
Detect pages where title = h1
Crawl the website to collect all pages where h1 and title tags are the same