WWW resolve
Also called: www vs non-www, www redirect, preferred domain
WWW resolve is picking one canonical version of your domain (either www.example.com or example.com) and 301-redirecting the other to it, so users and search engines always land on one address. Browsers treat the two as separate hosts, so consolidating them prevents split ranking signals and duplicate URLs.
A browser sees https://example.com and https://www.example.com as two different hosts. If both serve your site and neither redirects, Google can crawl and index both, split your backlinks and internal-link equity across them, and show whichever version it picks in results. Google removed the old “preferred domain” setting from Search Console in June 2019, so this now lives entirely on your server, not in a dashboard toggle.
The clean setup
Choose one version, then send a 301 redirect from the other to it. Google’s canonicalization docs call a redirect “a strong signal that the target of the redirect should become canonical.” Back it up with a matching rel="canonical" tag, list only the preferred version in your XML sitemap, and link internally to that version everywhere. These signals stack.
An nginx rule that forces non-www:
server_name www.example.com;
return 301 https://example.com$request_uri;Which one you pick (www or non-www) is not a ranking factor. In 2017 John Mueller called it “a brand preference with minimal SEO implications.” What matters is applying it site-wide, including the HTTP-to-HTTPS hop, so there is one redirect target and no chains. A common mistake is redirecting the homepage www to non-www while deep pages still resolve on both, which quietly reintroduces the duplicates you were trying to remove.
How it affects your traffic
When www and non-www both resolve, Google may index duplicate copies of every page, diluting the link authority that should concentrate on one URL and sometimes surfacing the wrong version in results. Consolidating them is one of the first things we check in a Technical SEO audit, alongside the HTTPS redirect and trailing-slash handling, because a broken redirect chain here quietly caps every other optimization you make. The fix is cheap and permanent: one redirect rule recovers split signals and keeps crawl budget on the pages that actually earn traffic.
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