Canonical Tag Scanner
Verify your canonical tags and get an instant SEO Health Score. Visualize your duplicate content risk and crawl budget efficiency in seconds.
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Master Your Duplicate Content Strategy
Canonical tags are the unsung heroes of SEO. They tell search engines which URL represents the master copy of a page. Without them, duplicate content issues can confuse Google, dilute your ranking power, and waste your crawl budget.
What is a Canonical Tag?
A canonical tag (rel="canonical") is a snippet of HTML code that defines the main version for duplicate, near-duplicate and similar pages. In other words, if you have the same content available under different URLs, you use canonical tags to specify which version is the main one and should be indexed.
Why are they critical?
Canonical Audit Features
Our scanner validates your implementation against Google's guidelines.
Self-Referencing
Checks if the page points to itself, a best practice to prevent scraper indexing.
Absolute URLs
Verifies that you are using full paths (https://...) instead of relative paths.
Rendered DOM
We execute JavaScript to see if your SPA or React app injects tags dynamically.
Cross-Domain
Validates tags pointing to external domains, essential for syndication attribution.
Conflict Detection
Alerts if you have multiple conflicting canonical tags on the same page.
Head Location
Ensures the tag is correctly placed in the `<head>` section, not the body.
Who Needs This Tool?
SEO Pros
Fix index bloating.
E-Commerce
Handle product variants.
Publishers
Manage syndication.
Developers
Verify SPA hydration.
How It Works
We parse your full HTML response to find the truth about your canonical strategy.
1. Fetch & Parse
We request your URL pretending to be a Googlebot smartphone to get the rendered HTML.
2. Validate
We check the `href` attribute for accessibility, absolute formatting, and recursion.
3. Verify
We ensure the target page actually exists (200 OK) and isn't a redirect or 404.
Why Use Our Scanner?
Duplicate Prevention
Stop self-cannibalization of your rankings by resolving duplicate content issues instantly.
Indexing Control
Direct search engines to the definitive version of your content to consolidate ranking power.
Audit Automation
Scan page headers and HTML automatically without needing to manually inspect source code.
Key Canonical Rules
Self-Referencing
Verifies that the page correctly points to itself as the original source (safety against scrapers).
Absolute Context
Ensures full absolute URLs (https://...) are used instead of relative paths to avoid ambiguity.
Cross-Domain
Validates external canonicals, essential for attributing credit when syndicating content.
Header Placement
Confirm that the tag is located high in the <head> section where crawlers expect it.
Frequently Asked Questions
Is a self-referencing canonical tag necessary?
Yes, it is highly recommended. It acts as a safeguard against scrapers and unexpected URL parameters, telling Google "this URL is definitely the one I want indexed."
Can I use canonical tags across different domains?
Yes! Cross-domain canonical tags are essential if you syndicate content on platforms like Medium or LinkedIn. It ensures the original site gets the credit.
What happens if I have multiple canonical tags?
Having multiple canonical tags on a single page confuses search engines, and they may ignore all of them. Ensure only one valid tag is present.
Does this tool check HTTP headers?
Our scanner primarily checks the HTML source code. While canonicals can be set in HTTP headers (useful for PDFs), the HTML tag method is the most common standard.
What if Google ignores my tag?
Google treats canonical tags as strong hints, not absolute directives. If content signals or other factors (like sitemaps) contradict the tag, Google may choose to index what it considers the original.
Do I need canonical tags for unique pages?
Yes. Self-referencing canonicals prevent duplicates created by URL parameters (e.g., tracking codes) from being indexed as separate pages.