What does HTTP status 303 (Redirect Method) mean?

HTTP_STATUS_REDIRECT_METHOD

A common use is the POST/redirect/GET pattern: after accepting form data, the server returns 303 and a Location header for a resource that describes the result.

The redirect target is not a substitute for the original request body. Clients normally follow 303 with GET or HEAD, avoiding an accidental repeat of the submitted operation.

303 is commonly used after a state-changing request to direct the client to a separate result resource. Following it with GET avoids accidentally repeating the original POST while obtaining the result representation. Clients should use the Location target supplied by the server instead of constructing a presumed result URI.

RFC 9110: HTTP Semantics