Canonical Tag Checker
Inspect HTML <link rel='canonical'> tags and HTTP response headers. Detect self-referencing canonicals, cross-domain declarations, protocol mismatches, and duplicate tag errors.
What the Canonical Tag Checker Analyzes
Comprehensive evaluation of HTML <head> tags, HTTP response headers, protocol consistency, and destination HTTP health.
Self-Referencing & Master Declarations
Verifies whether the page includes a self-referencing canonical tag to prevent accidental duplicate indexing from URL tracking parameters (?utm_source).
Protocol & Subdomain Consistency
Detects protocol mismatches (http vs https), subdomain variations (www vs non-www), and trailing slash inconsistencies.
HTTP Header & HTML Tag Parsing
Inspects both DOM HTML <link rel="canonical"> tags and HTTP Link response headers, flagging duplicate declarations.
Destination Reachability & og:url Alignment
Checks if the declared canonical URL returns a live HTTP 200 OK status code and matches the OpenGraph og:url social metadata.
Canonical Tag Checker FAQs
<link rel="canonical" href="...">) is an HTML element in the page <head> (or HTTP header) that specifies the preferred master version of a web page to search engines.