HTTP status code 303 indicates that the requested resource is located at another URI, and the client should use the GET method to retrieve it. This status code is commonly used for redirection, particularly when the original request was made using the POST method. Using the 303 status code helps avoid the issue of incorrectly redirecting POST requests to GET requests, which can occur with 302 redirects.
Characteristics of 303 Redirects
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Method Change: If the original request was a POST, the client should use the GET method to access the new URI when the server returns a 303 status code.
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Temporary Redirection: A 303 redirect is temporary, and the client should continue using the original URI for future requests.
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Response Header: When returning a 303 status code, the server typically includes a
Locationheader that specifies the new URI.
Common Scenarios for 303 Status Code
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Post-Operation Redirection: After a user submits a form (POST request), the server may perform some operations and then redirect the user to a new resource or page. Using the 303 status code ensures that the client uses the GET method to access the new URI.
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Avoiding POST Redirect to GET: If a 302 redirect is used, some older browsers may incorrectly convert POST requests to GET requests. The 303 status code helps prevent this issue.
Example Response
HTTP/1.1 303 See Other
Location: https://www.example.com/result-page/
Content-Length: 0
In this example, the status code 303 indicates that the result of processing the original POST request can be found at https://www.example.com/result-page/. The client (such as a browser) should use the GET method to access this new URI after receiving the response.
Using the 303 status code helps maintain the semantic consistency of HTTP methods and ensures that redirection behavior aligns with expectations.