What Canonical URL means
A canonical URL is the one web address you want treated as the real, official version of a page when duplicates or near-duplicates of it exist.
A product with both a www and non-www homepage, or a marketing site and an app subdomain describing the same thing, needs to pick one canonical URL so directories and search engines do not treat them as competing pages.
Setting a canonical URL is not the same as blocking the other version from existing. It is a signal, not a redirect, and search engines can sometimes choose a different canonical than the one you set.
Check your canonical tags on your homepage and top pages, and make sure every directory listing uses that exact same URL instead of a redirect or a slightly different variant.
Why this matters for builders
List the same canonical URL everywhere so directories and crawlers do not split your identity.
Mistake builders make often
Some builders list a different URL variant on every directory — sometimes with a trailing slash, sometimes with 'www', sometimes with a tracking parameter — splitting their identity across versions.
What to do now
Run your domain through the Canonical URL Checker, then copy that exact address into every directory listing you update from now on.