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How can the improper use of rel=”alternate” and rel=”canonical” tags affect SEO?

Welcome to our technical site audit document! This article will explore the impact of improper use of rel=”alternate” and rel=”canonical” tags on a website’s SEO. Understanding these tags and their correct implementation is crucial for optimizing website performance, enhancing user experience, and improving search engine rankings. This document aims to provide concise information and actionable tips to address related issues effectively.


Rel=”alternate” and rel=”canonical” tags are essential elements of technical SEO. They play a vital role in signaling the preferred webpage version to search engines and handling alternative versions, such as language or regional variations. When used correctly, these tags can help consolidate the SEO value of duplicate or similar content, improve crawl efficiency, and prevent duplicate content issues.

The rel=”alternate” tag indicates the presence of alternative versions of a webpage, such as those in different languages or targeting different regions. It helps search engines understand the relationship between these variations and index them appropriately. On the other hand, the rel=”canonical” tag specifies the preferred version of a webpage when multiple versions with similar content exist. It helps consolidate ranking signals and avoids diluting SEO efforts.

Common Issues:

Improper use of rel=”alternate” and rel=”canonical” tags can lead to issues hindering website performance and SEO efforts. Here are some common problems to be aware of:

  1. Incorrect implementation: Failing to include or misuse the rel=”alternate” tag can result in search engines not correctly recognizing and indexing alternate webpage versions. This can lead to missed opportunities to reach specific language or regional audiences.
  2. Misconfiguration: Incorrectly specifying the rel=”canonical” tag can cause search engines to misunderstand the preferred version of a webpage. This can result in indexing the wrong version, causing confusion and potential keyword cannibalization.
  3. Missing or broken tags: Omitting the rel=”alternate” or rel=”canonical” tags can lead to search engines treating different webpage versions as separate entities. This can fragment the SEO value across multiple URLs, affecting rankings and leading to duplicate content concerns.
  4. Inconsistent implementation: Using inconsistent or conflicting rel=”alternate” and rel=”canonical” tags across different webpage versions can confuse search engines and prevent them from understanding the relationships between the pages. This can negatively impact indexing and ranking.

Impact and Consequences:

Improper use of these tags can harm website performance, user experience, and SEO. The consequences include:

  1. Keyword dilution: When search engines index multiple webpage versions instead of consolidating ranking signals, it can dilute the SEO value across these variations. As a result, the preferred version may not receive the full benefit of accumulated backlinks and engagement metrics, leading to lower rankings.
  2. Duplicate content penalties: If search engines identify multiple versions of the same content without clearly indicating the preferred version, they may penalize the website for duplicate content. This can result in lowered rankings, decreased organic traffic, and reduced visibility in search results.
  3. Crawl inefficiency: When search engine crawlers encounter inconsistent or broken rel=”alternate” and rel=”canonical” tags, it can lead to inefficient crawling and indexing. This inefficiency can delay the discovery and indexing of important pages, reducing their visibility in search results.

Addressing Issues:

To mitigate the negative impacts of improper use of rel=”alternate” and rel=”canonical” tags, consider the following tips and best practices:

  1. Implement tags correctly: Ensure that rel=”alternate” tags are correctly placed in the header section of each webpage version, indicating the alternate URLs. Use appropriate attributes like “hreflang” to specify the language or region. For rel=”canonical” tags, place them in the header section of the preferred version, pointing to itself as the canonical URL.
  2. Verify tag implementation: Regularly audit your website to check for missing, misconfigured, or broken rel=”alternate” and rel=”canonical” tags. Use SEO auditing tools or browser extensions to help identify and validate these tags across different pages.
  3. Ensure consistency: Maintain consistency in using rel=”alternate” and rel=”canonical” tags across all webpage versions. Use the same attribute values and ensure they accurately reflect the relationships between the pages.
  4. Test and monitor: After implementing the tags, monitor their performance using search engine tools and web analytics. Keep an eye on indexing and rankings to ensure that search engines correctly understand the preferred versions and index them accordingly.
  5. Avoid self-referencing canonicals: Ensure that a webpage’s rel=”canonical” tag does not point to itself as the canonical URL. This can lead to confusion and result in pages being excluded from search engine indexes.
  6. Keep tags updated: If you change your website’s structure, content, or alternate versions, update the corresponding rel=”alternate” and rel=”canonical” tags accordingly. This ensures search engines have the most accurate and up-to-date information about your preferred versions.


Understanding the proper implementation of rel=”alternate” and rel=”canonical” tags is crucial for optimizing website performance, improving user experience, and enhancing SEO. By addressing the common issues related to these tags, you can avoid negative consequences such as keyword dilution, duplicate content penalties, and crawl inefficiency. Regularly audit and monitor your website to ensure the correct usage of these tags across all versions of your webpages. Doing so will optimize your website’s SEO value, improve search engine rankings, and provide a better experience for your users. Remember to refer to this document whenever you encounter issues or challenges related to the improper use of rel=”alternate” and rel=”canonical” tags during your site audits.


Larry Norris

With over 5 years of experience in agency work as an SEO Manager, I am proud to have assisted many clients in achieving higher search engine rankings and a stronger online presence. My successful track record includes top 3 rankings in SERPS, the attainment of featured snippets, and increased website domain authority.