301 vs 302 Redirects Compared: HTTP Methods and SEO

HTTP redirects instruct web browsers and search engine crawlers to forward a request from one URL to another location. Status codes 301 and 308 declare permanent URL moves, passing canonical equity and ranking signals to the new destination. Status codes 302 and 307 declare temporary diversions, keeping the original URL indexed while routing visitors forward. Choosing the correct status code ensures proper search indexing.

How HTTP redirects work in web architecture

An HTTP redirect is a server response that informs an automated client or web browser that the requested resource resides at a different location. Instead of delivering an HTML document body, the origin server returns a 3xx redirection status code paired with an HTTP Location response header containing the target destination URL.

When a client receives a 3xx response, it parses the Location header, establishes a connection to the new destination, and issues a secondary HTTP request. For human users, modern browsers execute this sequence in fractions of a second, rendering the final page automatically without requiring manual navigation.

HTTP Redirection Handshake:
Browser / Googlebot                 Origin Web Server
       │                                   │
       │─── GET /old-url HTTP/1.1 ────────►│
       │                                   │
       │◄── HTTP/1.1 301 Moved Permanently │
       │    Location: /new-url ────────────│
       │                                   │
       │─── GET /new-url HTTP/1.1 ────────►│
       │                                   │
       │◄── HTTP/1.1 200 OK ───────────────│
       │    (Serves HTML content)          │

For search engines like Google and Bing, redirects perform two distinct technical functions: routing discovery and transferring ranking signals. While any 3xx code forwards an automated crawler over the network, the specific numeric code dictates whether search algorithms consolidate link equity, transfer historical rankings, and swap indexed URLs in search results. Understanding this mechanism is fundamental to automated web crawlers.

The Internet Engineering Task Force (IETF) formally standardized four primary redirection codes across RFC 9110 and RFC 7538: 301, 302, 307, and 308. These codes form a clean two-by-two matrix dividing permanent from temporary intent, and method-mutating from method-preserving behavior.

301 Moved Permanently: Signals, canonicalization, and browser caching

An HTTP 301 Moved Permanently status code signals that the requested resource has been assigned a new permanent URI and that future references should use the target address. When Googlebot encounters a 301 redirect, it treats the destination URL as the new canonical version of the document.

From an organic search perspective, a 301 redirect transfers accumulated PageRank, anchor text context, and historical ranking signals from the original URL to the new destination. Google Search Central documentation confirms that 301 redirects pass full ranking equity without mathematical link dampening. Over successive crawl cycles, Google drops the old URL from search engine result pages and displays the new destination in its place.

Signal Transfer with 301 Redirect:
Old URL (High PageRank, Established Backlinks)
       │
       ▼  HTTP 301 Moved Permanently
       │
New Canonical Destination (Inherits Backlink Equity, Ranking Positions, and Index Status)

A crucial technical characteristic of 301 redirects is aggressive browser caching. When a web browser encounters a 301 response that lacks restrictive Cache-Control headers, the browser caches the redirection directive locally on the client machine. If the user attempts to visit the old URL again in the future, the browser redirects immediately using its local cache without issuing an HTTP request to your server.

This persistent caching makes reverting a mistaken 301 redirect notoriously difficult. Even if an engineer removes the redirect rule from the server, existing visitors will continue to be redirected by their local browser cache until their cache expires or is cleared manually.

However, historical web browsers introduced an unintended side effect with 301 responses: request method mutation. If a client submits a form via an HTTP POST request and the server responds with a 301 redirect, older browsers automatically rewrite the subsequent request method to GET, stripping the submitted request body payload entirely.

302 Found: Temporary routing without signal transfer

An HTTP 302 Found status code indicates that the requested resource resides temporarily under a different URI. Because the relocation is temporary, clients should continue using the original URL for future requests.

For search engine indexing, a 302 redirect acts as a temporary forwarding instruction without transferring canonical ownership. When Googlebot crawls a 302 redirect, it follows the Location header to fetch and inspect the destination content, but it retains the original source URL inside the search index. All external link equity, PageRank signals, and ranking positions remain attached to the original address.

Indexing Behavior with 302 Redirect:
Source URL (Retains Search Rankings, Canonical Authority, and Index Presence)
       │
       ▼  HTTP 302 Found (Temporary Routing)
       │
Temporary Destination (Served to Visitors; Does Not Inherit Long-term Signals)

A 302 redirect is appropriate in specific operational scenarios:

• E-commerce Out of Stock: Temporarily routing shoppers from a temporarily unavailable product to an equivalent category page.
• Geotargeting and Language Routing: Forwarding international users to localized regional subfolders based on IP detection.
• A/B Split Testing: Splitting traffic between two design variations without transferring search equity to the temporary test variant.
• Scheduled Server Maintenance: Directing users to a temporary maintenance notice while core database migrations execute.

Unlike 301 redirects, HTTP 302 responses are not cached by web browsers by default. Every client request reaches the origin server, allowing webmasters to remove or alter the routing rule instantly.

Like status code 301, historical implementations of 302 suffer from method mutation. When early browsers received a 302 response following a POST request, they universally converted the subsequent request to a GET request. While this behavior was technically contrary to the original HTTP/1.0 specification, it became the established de facto browser standard.

307 Temporary Redirect: Preserving HTTP request methods

HTTP 307 Temporary Redirect was created in the HTTP/1.1 specification (RFC 7231, now RFC 9110) to resolve the ambiguity surrounding method mutation in 302 responses. The formal specification explicitly prohibits a user-agent from changing the HTTP request method when following a 307 redirect.

If a web browser or automated client sends an HTTP POST request containing form data or a JSON payload to a URL that returns an HTTP 307 redirect, the client must repeat the exact same POST request, with the exact same request body, against the new destination URL.

Method Preservation with 307 Redirect:
Browser ──► POST /checkout/pay (Body: Card Data) ──► Server
Server  ──► HTTP 307 Temporary Redirect (Location: /pay-v2) ──► Browser
Browser ──► POST /pay-v2 (Body: Card Data Preserved) ──► Server (Transaction succeeds)

In contrast, if that payment endpoint had returned a 302 Found response, historical browser behavior would have mutated the call into a GET request with an empty body, causing the payment processing script to fail.

From an SEO perspective, Googlebot treats an HTTP 307 redirect identically to an HTTP 302 Found response. It recognizes that the relocation is temporary, keeps the original source URL in the search index, and does not pass permanent link equity or canonical status to the destination address.

Status code 307 also appears frequently in modern web browsers as an internal pseudo-status code during HTTP Strict Transport Security (HSTS) enforcement. When a user enters an unencrypted http:// address for a domain enrolled in HSTS, the browser intercepts the connection locally and issues an internal 307 redirect to https:// without generating network traffic.

308 Permanent Redirect: Permanent signal transfer with method preservation

HTTP 308 Permanent Redirect is the permanent counterpart to status code 307, formally defined by the IETF in RFC 7538. It combines the permanent canonical consolidation of a 301 redirect with the strict method preservation of a 307 redirect.

When an origin server returns an HTTP 308 response, it instructs the client that the resource has permanently moved and that the request method must not be altered when following the Location header. A POST request directed to a 308 endpoint must remain a POST request at the destination address.

308 Method Preservation and Signal Transfer:
Client ──► PUT /api/v1/user ──► Server returns 308 (Location: /api/v2/user)
Client ──► PUT /api/v2/user (Payload preserved)
Google ──► Consolidates Canonical Signals and PageRank to /api/v2/user

Google officially recognizes HTTP 308 as a permanent redirect. Search systems treat 308 responses exactly like 301 redirects: PageRank transfers completely, canonical authority moves to the destination, and search results update to show the target URL over time.

Because status code 308 is permanent, browsers cache 308 responses aggressively, matching the caching behavior of 301 redirects. Software engineers building RESTful APIs, payment endpoints, and modern Single Page Applications should use 308 instead of 301 whenever preserving non-GET request bodies during permanent URL migrations is required.

Direct comparison matrix: Status, permanence, method preservation, and cacheability

Choosing between 301, 302, 307, and 308 requires evaluating two distinct technical axes: permanence (temporary versus permanent) and method behavior (method-mutating versus method-preserving). The following comparison matrix summarizes the architectural properties of each code.

When managing standard content websites where URLs are fetched exclusively using HTTP GET requests, status codes 301 and 308 produce virtually identical SEO outcomes. Similarly, status codes 302 and 307 behave identically for GET requests.

However, in web applications handling form data, account logins, shopping carts, and RESTful APIs, the distinction between method rewriting and method preservation is critical. Using 301 or 302 on a POST endpoint strips payload data, causing application failures, while 307 and 308 guarantee data integrity.

For a broader taxonomy of server status indicators, consult our comprehensive reference on HTTP response status codes.

SEO consequences: PageRank transfer, index swapping, and search consolidation

The selection of a redirection status code directly dictates how search engine ranking algorithms manage canonical authority, keyword associations, and user search impressions. Understanding these search mechanics prevents inadvertent visibility drops during site updates.

When Google processes a permanent redirect (301 or 308), its canonicalization pipeline initiates a signal transfer process:

1. Signal Consolidation: Inbound backlinks pointing to the old URL are mapped to the destination URL. Anchor text signals and historical user engagement signals transfer forward.
2. Index Swapping: The indexing scheduler marks the old URL for de-indexing and enters the destination URL into the primary search index.
3. SERP Representation: The search results page updates to display the destination URL, page title, and meta snippet.

Canonical Signal Consolidation Cycle:
Step 1: Googlebot discovers 301/308 redirect
Step 2: Crawl scheduler fetches destination URL to verify 200 OK state
Step 3: Canonical pipeline consolidates PageRank and anchor text
Step 4: Search index swaps old URL for new destination
Step 5: Browser caches prevent old URL from being requested

This consolidation process is not instantaneous. While a browser updates immediately, Googlebot must recrawl the old URL multiple times to verify that the redirect is stable, fetch the destination URL to confirm its content quality, and run canonical evaluation algorithms. On large websites, completing an index swap across thousands of URLs can take several weeks as detailed in how Googlebot discovers URLs.

If a webmaster accidentally uses a 302 or 307 temporary redirect during a permanent site migration, Google assumes the original URL will return shortly. Consequently, Google retains the old URL in the search index and withholds link equity from the new destination. If the temporary redirect remains in place for many months, Google’s algorithms may eventually infer that the move is permanent and execute a retroactive canonical swap, but relying on algorithmic inference creates unnecessary ranking volatility.

Performance impacts: Redirect chains, latency, and crawl efficiency

Redirects impose a measurable performance tax on web infrastructure and user experience. Every redirection step requires an additional round-trip time (RTT) over the network, including DNS lookup, TCP socket negotiation, TLS handshake, and HTTP request-response processing.

On high-latency mobile networks, an extra redirect hop can add hundreds of milliseconds of page load delay. This latency directly degrades Core Web Vitals metrics, specifically Largest Contentful Paint (LCP) and Interaction to Next Paint (INP).

Furthermore, compounding redirects create redirect chains. A redirect chain occurs when a request passes through multiple intermediary 3xx hops before reaching the final document:

Compounding Latency in Redirect Chains:
Client ──► HTTP 301 (/page) ──► HTTP 301 (/page/) ──► HTTP 301 (https://page/) ──► HTTP 200 OK
Network Delay: RTT 1 (120ms) + RTT 2 (120ms) + RTT 3 (120ms) = 360ms wasted latency

Redirect chains severely degrade search crawler efficiency. When Googlebot encounters a redirect chain, it must schedule separate fetch requests for each intermediate URL. If a chain exceeds five hops, Googlebot aborts the crawl, logging a redirect failure in webmaster reports as documented in our guide on redirect crawl errors.

Redirects also consume server capacity and deplete crawl budget efficiency. If search engine crawlers spend thirty percent of their daily requests traversing internal redirects, they have fewer connection cycles available to discover and index newly published content.

Engineering teams should eliminate internal redirect chains by following two core rules:

1. Update Internal Links: Audit your site architecture to ensure all internal hyperlinks, canonical tags, and XML sitemaps point directly to the final canonical URL.
2. Consolidate Server Rules: Merge multiple forwarding rules (such as HTTP-to-HTTPS, non-www-to-www, and trailing slash normalization) into a single server-level rewrite block.

Adhering to these principles ensures that users and search spiders reach canonical content with zero unnecessary latency as explained in Search Engine Basics.

Frequently asked questions

Does a 301 redirect transfer full PageRank in Google?

A 301 redirect transfers full PageRank in Google without link decay or signal loss. Google Search Central representatives have confirmed that 301, 302, 307, and 308 redirects pass thirty percent to one hundred percent of ranking equity, with permanent codes transferring canonical signals completely.

When should I use a 302 redirect instead of a 301?

You should use a 302 redirect when a URL relocation is temporary and you intend to restore the original page in the future. Common scenarios include short-term promotional landing pages, A/B testing variations, user location geotargeting, and temporary server maintenance routing.

What is the difference between a 301 and a 308 redirect?

The difference between a 301 and a 308 redirect is that a 308 redirect guarantees HTTP request method preservation. While a 301 redirect allows browsers to rewrite POST requests to GET requests, a 308 redirect strictly requires the client to repeat the original request method and payload.

Why was HTTP 307 introduced if 302 already existed?

HTTP 307 was introduced in the HTTP/1.1 specification to resolve ambiguity regarding request method mutation in 302 responses. Older browsers routinely transformed POST requests into GET requests upon receiving a 302 code, leading RFC 7231 to establish 307 as a strictly method-preserving temporary redirect.

Can browsers cache 301 redirects permanently?

Web browsers cache 301 redirects aggressively in local client storage unless the server sends explicit cache-control headers prohibiting caching. Because browsers may remember a 301 redirect indefinitely, reverting a permanent redirect can prove challenging for existing visitors until their local browser cache expires.

How do redirect chains harm search engine crawling?

Redirect chains harm search engine crawling by introducing compounding network latency and consuming server connection resources. Search engine bots will abort a connection if a redirect chain exceeds five to ten sequential hops, triggering crawl errors and preventing page indexation.

How long does Google take to update search results after a 301 redirect?

Google typically updates search results between a few days and several weeks after a 301 redirect is deployed. The speed of the update depends on how frequently Googlebot recrawls the original URL, the size of the website, and the authority of the domain.

What happens if I point a redirect back to itself?

Pointing a redirect back to itself creates an immediate redirect loop error. When a web browser or search engine crawler detects that URL A redirects to URL A, it terminates the request after several failed attempts and displays a connection error to the user.

Sources

• Google Search Central: Redirects and Google Search
• IETF RFC 9110: HTTP Semantics (Redirection 3xx)
• IETF RFC 7538: The Hypertext Transfer Protocol Status Code 308 (Permanent Redirect)
• Mozilla MDN Web Docs: Redirections in HTTP