301 vs. 302 Redirects: Which to Use and When It Actually Matters for SEO
Redirect status codes tell browsers and search engines whether a URL change is permanent or temporary, and choosing the wrong one has real ranking consequences. Google has clarified that both 301 and 302 redirects can pass signals when the redirect is used correctly, but the practical guidance for permanent changes still strongly favors 301 for clarity and reliability across all crawlers and tools, not just Google.
301: Permanent Redirect
Use a 301 when a URL has changed for good — a page moved to a new path, a product was consolidated into another listing, or an entire site migrated to a new domain. A 301 tells crawlers this is the new permanent home, and ranking signals accumulated by the old URL should transfer to the new one. This is the correct default for the vast majority of SEO-driven redirect needs: site migrations, URL structure cleanups, and consolidating duplicate content.
302: Temporary Redirect
Use a 302 when a redirect is genuinely temporary — an A/B test variant, a page under maintenance with users routed to a holding page, or a seasonal promotion that will revert to the original URL afterward. A 302 tells crawlers to keep the original URL as the canonical, indexed version and not to transfer signals to the destination, which is exactly right when you intend to reverse the redirect later.
The Common Mistake: Leaving 302s in Place Permanently
The most frequent real-world error is a developer implementing a 302 (often because it's the default in many frameworks and CMS platforms) for what is actually a permanent change, then never revisiting it. Over months, this can leave ranking signals stranded on an old URL that no longer serves real traffic, while the actual live destination fails to accumulate the authority it should have inherited. Audit your redirect map periodically with Screaming Frog's response codes report, specifically checking that redirects intended as permanent are correctly returning 301, not 302.
Redirect Chains and Loops
A redirect chain — URL A redirects to B, which redirects to C — adds latency and can dilute the strength of the signal with each additional hop, and past 3-4 hops some crawlers may simply stop following the chain. A redirect loop (A to B to A) breaks the page entirely for both users and crawlers. After any major redirect project, crawl your full redirect map with a tool like Screaming Frog's "Redirect Chains" report to flag and flatten any chain down to a single, direct hop from the original URL straight to the true final destination.
Implement Redirects at the Server Level, Not in JavaScript
Server-side redirects (.htaccess rules, Nginx server blocks, redirect rules in your CDN or hosting panel) are read before any page content loads and are unambiguous to every crawler. Client-side JavaScript redirects (window.location) require a browser to execute JavaScript first, are slower for users, and carry more risk of being handled inconsistently by different crawlers — reserve JavaScript redirects only for edge cases where a server-level rule genuinely isn't possible.
Redirects for Site Migrations Deserve Extra Care
During a full domain or platform migration, build a complete URL-to-URL redirect map before launch rather than relying on generic pattern-based rules alone — a 1:1 mapping preserves the most signal and avoids sending users and crawlers to loosely related pages. Test the full map in staging, and monitor Search Console's Crawl Stats and Indexing reports closely for the first few weeks after launch, since migration-related redirect mistakes are one of the most common causes of sudden traffic drops in technical SEO. For a deeper look at this, see our guide, Building Topical Authority with Content Hubs.
Keep the Redirect Map After Launch
Don't delete your redirect rules once traffic appears stable — old inbound links from years-old backlinks, bookmarks, and social shares keep arriving for a long time after a migration, sometimes indefinitely. A well-maintained, permanent redirect map is a small ongoing cost that continues protecting link equity and user experience well beyond the initial migration window. For a deeper look at this, see our guide, Sitemaps, Robots.txt & Canonicalization.