301: Permanent. 302: Temporary. The Difference Matters.
A 301 redirect tells search engines: "This page has permanently moved to a new URL. Transfer all ranking signals to the new URL."
A 302 redirect tells search engines: "This page has temporarily moved. Keep the original URL in the index. Do not transfer ranking signals."
When to Use 301
Page permanently moved to a new URL. Old domain redirecting to new domain. HTTP to HTTPS migration. Any URL change that is not going back.
This is what you want 90% of the time.
When to Use 302
A/B testing where you want to preserve the original URL in the index. Temporary maintenance pages. Geolocation-based redirects where the original URL should remain canonical.
This is rare. Much rarer than most developers think.
The Common Mistake
Using 302 when you mean 301. It happens constantly. A developer sets up a redirect, uses 302 by default (many servers default to 302), and nobody checks.
Result: Google keeps the old URL in the index. Link equity does not transfer. Your new page has no ranking power.
We have seen this exact mistake tank rankings on big sites. Multiple times across our 500+ campaigns.
How to Check
Crawl your site. Check every redirect's status code. Every permanent redirect should be 301 (or 308). Every temporary redirect should be 302 (or 307). If you see 302s that should be 301s, fix them. And watch for redirect chains while you are at it. Run a full redirect audit quarterly. Google's crawling documentation covers how Googlebot handles different redirect types.
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