Redirect (301, 302)
A redirect sends users and search engines from one URL to another. A 301 is permanent and passes ranking signals to the new URL. A 302 is temporary and tells search engines the original URL will return, so it consolidates less.
Why it matters for your rankings
Redirects are how you move content without losing what it earned. Get them right and rankings transfer within weeks. Get them wrong and years of accumulated authority evaporate at launch.
The failures are predictable and preventable. Redirecting every old URL to the homepage is treated as a soft 404 and passes nothing. Chains of three or four hops lose value at each step and slow the page. Using 302 for a permanent move leaves Google indexing the old URL indefinitely. Migrations are where all of this surfaces at once, which is why a URL-by-URL redirect map, built before launch rather than after, is the difference between a smooth replatform and a traffic collapse.
How to check it on your site
Map old URLs to real equivalents
Every removed URL should point at the closest relevant page, not a generic category or the homepage.
Eliminate chains
Crawl the site and flag any URL that passes through more than one hop before resolving. Point each source directly at the final destination.
Use the right status code
301 for permanent moves, 302 only when the original URL genuinely returns.
Verify after launch
Re-crawl within 48 hours of a migration and check Search Console for a spike in 404s.