What it is
Most sites can be reached more than one way without anyone intending it — with or without www, with or without a trailing slash, sometimes with tracking text added to the end of the address. To a visitor, these all look and feel identical. To a search engine, they can look like several separate pages that all happen to have the same content. A canonical tag is a short line of code that simply says "out of all these possible addresses, this one is the real, preferred version — send credit and rankings here."
Why it matters
Without it, search engines have to guess which version of a page to treat as the main one, and they can guess wrong — splitting a page's visibility across two or three near-identical addresses instead of concentrating it into one strong result. It can also occasionally show the wrong version of a page (an old, outdated address instead of the current one) in search results, which looks sloppy to anyone who clicks through.
How to fix it
- Decide on one preferred, final version of your page's address — including whether it uses
wwwand whether it ends in a slash — and use that consistently everywhere on your own site. - Add
<link rel="canonical" href="https://yourdomain.com/your-page">inside the<head>section of that page's code, pointing at the exact preferred address. - If you use a website builder (Squarespace, Wix, Webflow, WordPress with an SEO plugin like Yoast), this is usually generated for you automatically — look for a "canonical URL" field in that page's SEO settings rather than editing code by hand.
- Make sure every page points its canonical tag at itself (its own preferred address), not at your homepage — a common mistake that can accidentally hide every other page from search results.
- Re-run your Launch Readiness check to confirm the tag is now detected and points at the right address.