Redirect() vs RedirectPermanent() in ASP.NET MVC

The key difference is that RedirectPermanent sends an HTTP 301 (Moved Permanently) status code, indicating a permanent redirection, while Redirect sends an HTTP 302 (Found) status code, indicating a temporary redirection.

Use RedirectPermanent when a resource is permanently relocated and is no longer accessible at its original location. Browsers typically cache the HTTP 301 response and handle future redirects automatically.

Use Redirect when the resource might still be available at the same URL in the future.

For example:

If a deleted user’s details are requested at /user/{userid}, redirect to /user/does-not-exist. Use Redirect since the original URL might become valid again if the user is restored.

If the user will never be restored, use RedirectPermanent so the browser automatically redirects to /user/does-not-exist in future requests. If the user may be restored, use a regular Redirect.

How to use RedirectPermanent in a controller action?

public ActionResult OldPage()
{
    // Redirect to a new URL with a permanent 301 redirect status
    return RedirectPermanent("/new-page");
}

In this example, when a user accesses the OldPage action, they will be permanently redirected to /new-page. The browser will also update its cached URL for future requests.

RedirectPermanent should be used when the resource has permanently moved or will never return to its original location.