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G3getByteRush

Canonical Checker

Check a page's canonical tag for missing, duplicate, or mismatched URLs.

100% client-side — your data is processed in this browser tab and never uploaded anywhere.

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How to use this tool

  1. Optionally enter the page's own URL, so the tool can tell you whether the canonical is self-referencing.
  2. Paste the page's HTML source.
  3. Review the result — missing, duplicate, self-referencing, or pointing elsewhere.

Why check canonicals in the browser?

This reads the HTML you paste locally with the browser's own DOMParser — nothing is transmitted anywhere, so it works for pages that aren't publicly reachable yet.

Frequently asked questions

What is a canonical tag for?
It tells search engines which URL is the "master" version when the same or similar content is reachable at more than one URL (e.g. with and without a trailing slash, or with tracking parameters) — preventing duplicate-content dilution.
Is it bad if the canonical points to a different URL?
Not necessarily — that's intentional on syndicated content or paginated series pointing back to a main page. It's only a problem if it happens by mistake, e.g. every page pointing to the homepage.
What happens with multiple canonical tags?
Search engines generally use only the first one and may treat the page as an unreliable signal overall — this should be fixed regardless of which one is "correct."

How GetByteRush compares

Most free tools for this online work the same way: you upload your file to their server, wait, then download the result — which means your file (and often your email, for a "free" account) sits on someone else's infrastructure. Here's the actual difference:

FeatureGetByteRushTypical online canonical checkers
Works on staging/private pagesYes — paste-basedUsually no
Data ever leaves your deviceNo — 100% client-sideOften yes

("Typical online tools" reflects publicly documented behavior of common free file-processing sites as of 2026 — always check a specific competitor's own privacy policy and pricing page, since these details change.)