HTTP 301 Moved Permanently

The resource has a new permanent URL given in the Location header. Clients should update their references.

3xx · Redirection✗ not retryable — fix the request instead

In AI APIs specifically

API base-URL typos (http vs https, trailing slash) often surface as 301s that drop POST bodies on redirect.

Update to the URL in the Location header.
Use https and the exact documented base URL — redirects can downgrade POST to GET.

The resource temporarily lives at a different URL.

Conditional GET: the cached copy is still valid; the server sends no body..

Like 302 but the method and body MUST be preserved when following the redirect..

Like 301 but the method and body MUST be preserved.