What is the difference between 301 and 308?

Both are permanent redirects, but 301 historically allowed clients to change POST to GET, while 308 guarantees the method and body are preserved. Use 308 when redirecting non-idempotent endpoints permanently.

Should I use 301 or 302 for SEO?

Use 301 (or 308) for permanent moves so search engines transfer ranking signals to the new URL. 302 and 307 are temporary and tell engines to keep indexing the original URL.

What does 304 Not Modified do?

304 answers a conditional GET when the client's cached copy is still fresh. The server sends no body, saving bandwidth, after validating an ETag via If-None-Match or a date via If-Modified-Since.

When should I use 303 See Other?

Use 303 after a POST to redirect the browser to a result page that must be fetched with GET. This is the Post/Redirect/Get pattern that prevents duplicate form submissions on refresh.

Is 305 Use Proxy safe to use?

No. 305 is deprecated and ignored by modern browsers for security reasons. Do not rely on it; configure proxying through normal infrastructure instead.

HTTP 3xx Redirect Codes

HTTP 3xx redirect status codes

The 3xx class tells the client that further action — usually following a Location URL — is needed to complete the request. The nuances matter: some redirects are permanent and pass SEO signals, others are temporary; some preserve the original HTTP method and body, others quietly rewrite it to GET. Pick the wrong one and you can break a POST, lose search rankings, or create redirect loops. Search the reference above by code or keyword to compare permanence, method handling, and caching.

How it works

A redirect response carries a Location header pointing to the new target. The browser then issues a fresh request to that URL. Two independent dimensions distinguish the codes. First, permanence: 301/308 are permanent (update bookmarks, transfer ranking), while 302/303/307 are temporary. Second, method preservation: 307 and 308 guarantee the method and body survive the redirect, 303 always switches to GET, and 301/302 historically allowed POST→GET rewrites that differ across clients. 304 Not Modified is the odd one out — it is part of conditional requests and caching, not navigation, and returns no body.

Tips and examples

For an HTTP→HTTPS upgrade or a permanent domain move, prefer 308 so POST requests are not silently downgraded, and so engines pass ranking to the canonical URL.
After a form POST, respond with 303 See Other to the confirmation page; refreshing then re-fetches that page with GET instead of resubmitting.
Support conditional requests: emit ETag/Last-Modified and answer matching If-None-Match/If-Modified-Since with 304 to cut bandwidth.
Avoid chains: redirecting A→B→C wastes round trips and dilutes link equity. Point every old URL directly at the final destination.

HTTP 3xx Redirect Codes

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HTTP 3xx redirect status codes

How it works

Tips and examples