Understanding HTTP Redirects: 301 vs 302
HTTP redirects are fundamental building blocks of the modern web, enabling websites to move content, consolidate URLs, manage domain migrations, and redirect traffic to appropriate locations. Two of the most important redirect types are 301 (Moved Permanently) and 302 (Found/Moved Temporarily), but despite their similar functionality, they have profoundly different implications for search engine optimization and user behavior. Choosing between them incorrectly can inadvertently harm your SEO, confuse users, or create maintenance nightmares down the road.
The core difference is deceptively simple: 301 redirects signal permanence while 302 redirects signal temporality. But this simple distinction ripples through the entire ecosystem of web crawlers, search engines, caching systems, and browser behavior. Understanding these implications allows you to deploy redirects strategically and maintain your site's search visibility during transitions.
HTTP Status Codes: The Foundation
What is an HTTP Status Code?
When your browser requests a web page, the server responds with both data and a status code. Status codes are three-digit numbers that communicate the outcome of the request:
- 1xx (100-199): Informational responses
- 2xx (200-299): Successful responses (200 OK is the standard success code)
- 3xx (300-399): Redirection messages
- 4xx (400-499): Client errors (404 Not Found, 403 Forbidden)
- 5xx (500-599): Server errors
Redirects fall within the 3xx category, with each variant conveying different information about why the user is being redirected and what this redirection means for their future interactions.
The 301 Redirect (Moved Permanently)
What It Means
A 301 status code tells the browser and search engines: "This resource has permanently moved to a new location. Update your bookmarks and records. If you request this URL again in the future, go directly to the new location."
Key Characteristics
Permanence: The 301 code explicitly signals that the change is permanent and won't be reversed. Search engines interpret this as "update all references to the new URL."
Link Equity Transfer: Search engines (particularly Google) transfer approximately 90-99% of the link authority, PageRank, and backlink value from the old URL to the new one. Rankings associated with the old URL typically transfer to the new URL.
Index Updates: Search engines update their indices to reflect that the old URL is no longer the primary location. They eventually remove the old URL from search results and display the new URL instead.
Bookmark and History Updates: Users' browsers may update bookmarks to point to the new URL automatically (though this behavior varies by browser).
Caching: 301 redirects are considered safe to cache, and browsers may cache them aggressively. Changing a 301 redirect later requires waiting for cache expiration or forcing browser cache clearing.
Use Cases for 301 Redirects
Site Migrations: Moving your entire site to a new domain
301 /old-site.com/ → /new-site.com/
URL Structure Changes: Reorganizing your site's URL hierarchy
301 /product/category/item → /products/item
Consolidating Duplicate Content: Merging multiple URLs into a single canonical version
301 /about-us.html → /about
301 /about-company.html → /about
Domain Consolidation: Redirecting one domain to another
301 www.old-name.com → www.new-name.com
Deleting Pages with Existing Equity: Rather than returning 404, preserving ranking value
301 /discontinued-product → /replacement-product
HTTPS Migration: Redirecting all HTTP URLs to HTTPS
301 http://example.com/* → https://example.com/*
SEO Implications of 301
Positive:
- Transfer ranking authority to new URLs
- Consolidate SEO value across multiple variations
- Maintain search visibility during site reorganization
- Indicate to search engines that a URL has legitimately moved
Considerations:
- Takes time for search engines to process (typically weeks to months)
- Some traffic may be lost during the transition period
- Temporary ranking fluctuations are common
- Backlinks continue pointing to old URLs until they're updated
The 302 Redirect (Found / Moved Temporarily)
What It Means
A 302 status code tells the browser and search engines: "This resource has temporarily moved, but the original URL is still valid. Continue using the original URL for now; this is just a temporary detour."
Key Characteristics
Temporality: The 302 code explicitly signals that the relocation is temporary. Search engines interpret this as "this is a short-term situation; don't update your records."
No Link Equity Transfer: Search engines do NOT transfer ranking authority to the destination URL. The original URL retains all ranking value and backlinks. The original URL remains the canonical version in search results.
Index Preservation: Search engines continue to index and display the original URL in search results, treating the 302 as a temporary routing mechanism.
No Automatic Bookmark Updates: User browsers don't update bookmarks, as they understand the redirect is temporary.
Lightweight Caching: 302 redirects are not typically cached as aggressively by browsers or intermediaries, making them easier to change.
Use Cases for 302 Redirects
A/B Testing: Temporarily redirecting traffic to test a new page design while maintaining SEO value
302 /products/ → /products-new-design/ (during testing)
Temporary Maintenance: Redirecting during system maintenance or updates
302 /checkout/ → /maintenance-message/ (during downtime)
Geographic Routing: Temporarily redirecting users to region-specific pages
302 /store → /store-region-specific/ (based on user location)
Promotional Redirects: Temporarily directing traffic to a special offer page
302 /main-product → /special-promo-version/ (during promotion period)
Temporary Content Moves: Moving content temporarily while retaining the original URL as the primary location
302 /article → /article-on-new-server/ (during migration phase)
Device-Based Routing: Redirecting mobile users to a mobile version while keeping desktop URL primary
302 /page → /page-mobile/ (for mobile devices, but less common with responsive design)
SEO Implications of 302
Ranking Preservation:
- Original URL retains all ranking value
- Useful for testing changes without losing SEO
- No long-term impact on search visibility
Disadvantages:
- Destination page doesn't benefit from ranking value
- Confusion if used inappropriately (302 instead of 301 for permanent changes)
- Search engines may eventually crawl the destination instead of following the redirect
When NOT to Use:
- Don't use for permanent moves (use 301 instead)
- Don't use for long-term changes
- Avoid using for more than a few weeks/months
Comparing 301 vs 302: Side-by-Side
| Aspect | 301 Redirect | 302 Redirect |
|---|---|---|
| Permanence | Permanent | Temporary |
| Link Equity | Transfers 90-99% | Retains on original |
| Search Index | Updates to new URL | Keeps original URL |
| Ranking Impact | Ratings transfer | Ratings preserved |
| Duration | Permanent (keep in place) | Short-term (weeks/months) |
| Use For | Permanent moves, migrations | Testing, maintenance, promos |
| Browser Behavior | May update bookmarks | No bookmark updates |
| Caching | Heavily cached | Lightly cached |
| Best Practice | Default for permanent changes | Used sparingly |
Common Mistakes with Redirects
Using 302 Instead of 301 for Permanent Moves
Problem: Site is migrated to a new domain but 302 redirects are used.
Result:
- Original domain retains all ranking value
- New domain doesn't receive ranking benefit
- Search engines continue indexing original domain
- Months later, potential duplicate content penalties
Solution: Always use 301 for permanent moves and plan to maintain 301 redirects for at least 1 year.
Using 301 for Temporary Changes
Problem: During A/B testing, a 301 redirect to a new page is implemented.
Result:
- Original URL loses all ranking value to test page
- If test fails, reversing the redirect is problematic
- New page now appears in search results instead of original
- Difficulty reverting to original structure
Solution: Always use 302 for temporary changes and A/B testing.
Redirect Chains
Problem: URL1 → URL2 → URL3 (multiple redirects in sequence)
Result:
- Each redirect consumes a small amount of ranking authority
- Slower load times
- Search engines may not follow the full chain
- User experience suffers
Solution: Redirect directly to the final destination (URL1 → URL3).
Long-Term 302 Redirects
Problem: 302 redirect set up years ago for a "temporary" maintenance page that's never changed back.
Result:
- Search engines get confused about canonical URLs
- Duplicate content issues
- Inconsistent index updates
- Potential penalties
Solution: Either convert to 301 if permanent, or proactively remove after truly temporary period ends.
Implementation Best Practices
When Implementing 301 Redirects
- Plan for Permanence: Understand that 301 redirects should remain in place for at least 1 year, ideally longer
- Update Backlinks: Over time, update external sites linking to old URLs
- Update Internal Links: Change internal links to point to new URLs
- Monitor Search Console: Track the transition in Google Search Console
- Maintain Old Domain: For domain migrations, keep old domain active (redirecting) for extended period
When Implementing 302 Redirects
- Document Reason: Note why the 302 is in place and when it should be removed
- Set Expiration: Plan a specific date to remove or convert the redirect
- Monitor Performance: Watch for unintended index changes or ranking impacts
- Plan Removal: Have a plan to remove the 302 redirect when the temporary situation ends
Advanced Redirect Considerations
Other Redirect Types
Beyond 301 and 302, other status codes exist:
303 (See Other): Tells the browser to use GET method for redirect (typically for form submission handlers)
307 (Temporary Redirect): Similar to 302 but guarantees HTTP method preservation
308 (Permanent Redirect): Similar to 301 but guarantees HTTP method preservation
Most use cases are adequately handled by 301 and 302.
Server-Level vs. Header Redirects
Redirects can be implemented at different levels:
HTTP Headers: Server sends redirect before any content (most efficient)
Meta Refresh Tags: HTML tag that triggers redirect (less efficient, bad for SEO)
JavaScript Redirects: JavaScript code that redirects (unreliable, not SEO-friendly)
Best Practice: Always implement redirects at server/header level for maximum efficiency and SEO benefit.
Conclusion
The choice between 301 and 302 redirects carries significant implications for SEO, user experience, and site maintenance. Use 301 redirects for permanent changes and site migrations, confident that search engines will transfer ranking authority to new locations. Reserve 302 redirects for genuinely temporary situations, maintaining them for only weeks or months before removal or conversion. By understanding the distinct purposes of each redirect type and implementing them appropriately, you maintain your site's search visibility, provide clear signals to search engines about your content structure, and create a better experience for both users and web crawlers navigating your domain.
