303 redirects are a redirect-type that will not pass any SEO value or “Juice” and will not remove pages out of a search engine index even if the pages are deleted from a domain’s server. This type of redirect is temporary and easily misinterpreted or misunderstood by older search engines.
Methodology for Handling 303 Redirects
The response to the request can be found under a different URL and SHOULD be retrieved using a GET method on that resource. This method exists primarily to allow the output of a POST-activated script to redirect the user agent to a selected resource. The new URL is not a substitute reference for the originally requested resource. The 303 response Must NOT be cached, but the response to the second (redirected) request might be cacheable.
Developed to prevent a form from being resubmitted after an HTTP Post request. As an example, a recent SouthWest Airlines issue caused customers to be charged multiple times from a deal they saw presented on their Facebook page. Once the user purchased a ticket, a type of redirect loop came into play, causing multiple credit card charges. 303 redirects are the exact type of redirect to use in this situation to avoid potential problems with technology. Additionally, the response the browser and engines receives comes from the CMS, not the server-level, which decreases page speed.
301 vs 302 Redirect
Over the years the 303 error has become outdated and replaced with the 302 redirect type. The 302 redirect, similar to the 303, also provides no SEO value to the pages involved and will not remove old pages from the search results.
303 redirects – Our Recommendations:
If you use 303 redirects, STOP right now and have someone help you setup the correct, most relevant redirects for your site.