In short. Google recommends the same structured data on all duplicate pages for the same content, while canonical signals identify a preferred URL.
Definition: Yes. For duplicate pages that contain the same content, Google recommends placing the same structured data on every duplicate, including pages that are not the canonical URL. The structured data instruction covers markup coverage, while canonicalization covers the preferred URL among duplicate or very similar pages.
Key facts
- Google's general structured data guidelines say that duplicate pages for the same content should carry the same structured data on all page duplicates.
- The same policy says structured data must be a true representation of the page content and should be placed on the page it describes.
- A structured data issue can lead to a manual action that removes rich result eligibility; Google says this does not affect how the page ranks in web search.
- Google's canonical URL documentation lists redirects,
rel="canonical"annotations, and sitemap inclusion as canonicalization methods with different signal strengths. - Google says internal links should point to the canonical URL rather than a duplicate URL.
Why does Google recommend equivalent markup on duplicates?
Google's policy treats structured data as a description of the page that carries it. It says the markup must be a true representation of that page's content and places the markup on the page it describes. For a set of duplicate pages representing the same content, the direct instruction is to place the same structured data on every duplicate, rather than limiting it to the canonical page.
This makes the markup consistent across the URLs that expose the content. The policy also says structured data pages should remain accessible to Googlebot: the page should not be blocked with robots.txt, noindex, or another access control method. Structured data can make a page eligible for a rich result, but eligibility depends on the applicable guidelines and Google's processing of the page.
Is this the same as choosing a canonical URL?
No. The two instructions address different parts of a duplicate set. Equivalent structured data concerns whether each page carries a truthful description of its content. Canonicalization concerns the URL that Google should prefer when several URLs contain duplicate or very similar pages.
Google's canonicalization documentation says a site can indicate its preference with redirects, a rel="canonical" link annotation, or sitemap inclusion. It describes redirects and rel="canonical" as strong signals and sitemap inclusion as a weak signal. Google can also determine a preferred version when a site supplies no canonical preference.
The canonical link belongs on every duplicate page and points to the preferred URL. Google's example is an HTML link in the document head:
<link rel="canonical" href="https://example.com/dresses/green-dresses" />
The canonical page can carry a self-referential canonical link as well. Google recommends absolute URLs for this link and says a canonical link is accepted only in the HTML head section.
What should a website implement?
Each duplicate page should expose the same structured data that describes the shared content. If a page contains a field whose value changes with the URL, that value needs to remain a truthful representation of the page carrying it. The policy's duplicate-page sentence is a recommendation, so it does not state a similarity threshold or define which page variations qualify as duplicates.
The URL signals should be handled separately. A canonical link can express the preferred URL, internal links can use that URL, and a sitemap can list preferred canonicals. Google's documentation says that canonicalization is intended to consolidate signals for similar or duplicate pages and to avoid spending crawling time on duplicate versions. It also says robots.txt is not a canonicalization method and that noindex blocks a page from Search, making it unsuitable for selecting a canonical within a single site.
Related terms
FAQ
Should you copy the exact JSON-LD text to every duplicate?
Keep the structured data equivalent for the shared content on each duplicate page. Google’s instruction concerns the same structured data on all page duplicates, while every page still needs markup that truthfully represents its own content.
Do you use the same canonical URL on every duplicate?
Yes, when one URL is the preferred version, place a rel="canonical" link on each duplicate pointing to that URL. Add a self-referential canonical link to the preferred page as well.
Can you use robots.txt to choose the canonical page?
No. Google's canonicalization guidance says not to use robots.txt for canonicalization. A redirect, a rel="canonical" link, or sitemap inclusion supplies the documented canonicalization signal.
Sources
- Google Search Central, "General Structured Data Guidelines", undated
- Google Search Central, "How to Specify a Canonical with rel="canonical" and Other Methods", undated
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