HTTP Redirects Explained — 301 vs 302 vs 307 vs 308 (Permanent & Temporary)

Core Concepts

301 Moved Permanently — the SEO redirect

301 tells search engines to transfer link equity (PageRank) to the new URL permanently. Use 301 for canonical URL changes: HTTP→HTTPS upgrades, www→apex consolidation, and permanent URL restructures. Search engines cache 301 mappings aggressively — once indexed, old URLs disappear from SERPs. Do NOT use 301 for temporary A/B tests or holiday landing pages.

302 Found — the historical ambiguity

302 is the original 'temporary redirect.' The spec is unclear about method preservation: many browsers convert POST to GET after a 302, while some proxy caches keep the original method. This ambiguity is why 307 and 308 were created. 302 is still widely used for post-login redirects and maintenance pages, but if method preservation matters, prefer 307.

303 See Other — the PRG pattern

303 Always forces a GET — even if the original request was a POST. This is the standard Post/Redirect/Get pattern: the browser POSTs a form, the server returns 303 with a confirmation page URL, and the browser GETs the confirmation. This prevents accidental form re-submission on refresh. Use 303 when redirecting after successful form submission or resource creation.

307 Temporary Redirect & 308 Permanent Redirect — method-preserving

307 and 308 are the unambiguous successors to 302 and 301. 307 is a temporary redirect that preserves the original HTTP method — if you POST to /old, the redirect to /new will also be a POST. 308 is the permanent equivalent: it preserves the method AND tells search engines to transfer link equity (like 301 does). Use 308 for permanent redirects of non-GET endpoints (e.g., POST-only API routes moving to a new path).

Choosing the right redirect code

Permanent URL change (GET): 301. Permanent URL change (non-GET): 308. Temporary redirect (method doesn't matter): 302. Temporary redirect (preserve method): 307. Post-submission (always GET): 303. If in doubt: 307 is safer than 302 because it's unambiguous — all modern clients preserve the method.

Frequently Asked Questions