Does Canonical URL Checker upload my files to a server?

No. Canonical URL Checker runs entirely in your browser using on-device processing, your files never leave your device.

Canonical URL Checker

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

Runs in your browser

See it in action

Your inputReady to use

Page URL (optional, to check it’s self-referencing)Page HTML (paste the <head> section, or the whole page)

Sitemap Generator

Generate an XML sitemap from a list of page URLs.

Meta Tag Generator

Generate title, description, Open Graph and Twitter Card meta tags.

SERP Preview

Preview how your page will look in Google search results.

Open Graph & Twitter Card Preview

Preview how a link will look when shared on Facebook, LinkedIn and X.