Technical Foundations · 1.8
Canonicalization
If the same page accidentally exists at two addresses (for example, both with and without “www” at the front), this is a small note in the code saying “this one's the real page — ignore the other.”
Why this matters
The customer’s side
Largely invisible — but if Google ends up showing the “wrong” duplicate version, a customer might land on an older or less complete copy of a page than the one you'd actually want them to see.
The search engine’s side
Without it, Google has to guess which page counts
Without it, Google has to guess which version to trust, and ranking strength can get split or wasted across two competing pages rather than concentrated on one strong one.
How to check yours
Method 1 — Check a handful of pages by hand
quick, and enough to catch an obvious sitewide problem.
- 1.Open your homepage, right-click, click “View Page Source” (or Cmd+Option+U on Mac).
- 2.Search (Cmd+F) for “canonical.”
- 3.Check the address inside that line matches the page you're actually on.
- 4.Repeat on 2–3 other key pages.
- 5.Also check whether “www” and non-“www” versions of your site both load separately, rather than one redirecting to the other.
Method 2 — Screaming Frog, for every page at once
checking pages one at a time misses problems buried deeper in the site — a full crawl catches all of them together.
- 1.Download Screaming Frog, free, and crawl your site.
- 2.Click the “Canonicals” tab.
- 3.Look for anything marked missing, or pointing to a different URL than the one it's on.
How to fix what you find
Canonical tags missing entirely
ask a developer to add a self-referencing canonical tag sitewide — every page pointing to itself by default, which quietly prevents most of these problems before they start.
“www” and non-“www” both load separately
this is usually a single setting at hosting level — ask your host or developer to set up a permanent (301) redirect from one version to the other.
Keeping on top of it
This tends to quietly reappear with site updates, whether or not anyone's watching for it — worth a check every few months.
How Reyse handles this
Done With You
we diagnose it and give you the exact brief to hand your developer.
Done For You
we manage the developer relationship and this fix directly, ongoing.