301 redirect
A server-side permanent redirect that tells crawlers a URL has moved for good and that ranking signals should consolidate on the…
TechnicalPermanent Redirect
308 redirect
A permanent redirect equivalent to 301 for indexing purposes, but which forbids changing the HTTP method when following it.
In full
308 was added to correct a historic ambiguity in 301, where clients often converted POST to GET. Google states it treats 308 the same as 301 for canonicalisation. It is the safer choice for API endpoints and form submission targets; for ordinary page moves 301 and 308 are interchangeable.
Example
A framework's trailing-slash normalisation emits 308 rather than 301, with no difference in how Google consolidates signals.
Related terms
307 redirect
A temporary redirect that, unlike 302, guarantees the HTTP method and body are preserved; also the code browsers report for internal HSTS…
Canonicalization
The process by which a search engine groups duplicate or near-duplicate URLs into a cluster and picks one representative URL to index and…
HTTP status codes
Numeric codes in an HTTP response that tell crawlers how to treat a URL: 200 index it, 3xx follow the redirect, 404/410 drop it, 5xx come…
Site migration
Any change to a site's domain, URL structure, platform, template or content organisation that materially affects how search engines see it.