Duplicate content is a common technical issue that can hinder the performance of a website in search engines. Common technical issues that can lead to duplicate content:
- URL parameters: URL parameters, such as session IDs or sorting options, can cause multiple URLs to display the same content, leading to duplicate content issues.
- Printer-friendly versions: Printer-friendly versions of pages can also lead to duplicate content if not handled properly.
- WWW vs non-WWW: Duplicate content can also occur when a website is accessible with both www and non-www versions of the domain name.
- HTTP vs HTTPS: Duplicate content can also occur when a website is accessible using both HTTP and HTTPS versions of the domain name.
- 302 status code: When contents are released under a new URL and a 302 (temporary redirect) has been chosen instead of a permanent redirect.
- Same language, different country version: Releasing e.g. UK content to the US creates a duplicate content issue for the US content if hreflang is not used (correctly)
- Mobile versions: Mobile versions of a website can also lead to duplicate content if not properly configured.
- Syndicated content: Duplicate content can occur when the same content is published on multiple websites, including syndicated content or content that is scraped from other websites.
To prevent technical duplicate content issues, it’s important to implement proper canonicalization and redirects, as well as to configure your website to use a preferred domain name (www or non-www) and to properly handle mobile versions of your website. Additionally, you should avoid publishing duplicate content on multiple websites, and ensure that any syndicated content is properly attributed to the original source.
How to prevent technical duplicate content?
- Use rel=”canonical” tags: Adding a rel=”canonical” tag to pages with similar content can help tell search engines which page is the original and should be indexed.
- Avoid using parameters in URLs: URLs with parameters, such as those used for sorting and filtering, can lead to duplicate content issues. Consider using static URLs instead.
- Implement a 301 redirect: If you need to change the URL of a page, it’s important to implement a 301 redirect to send visitors and search engines to the new URL and remove the old URL out of the index.
- Avoid using session IDs in URLs: URLs with session IDs can also lead to duplicate content issues. Consider using cookies or other methods to store session information instead.
- Use the HTTPS & WWW version of your site: Redirect rules from HTTP to HTTPS version of your site, as well as non-WWW to WWWW version of your site, can help prevent duplicate content issues and improve the security of your website.
- Use hreflang: Set hreflang to help Google understanding which landing page should be index in which country.
- Use a robots.txt file: Using a robots.txt file to disallow search engines from indexing duplicate or redundant pages can also help prevent duplicate content issues. (only for full category trees, not recommended for individual URLs)