What does HTTP 303 mean?
The response to the request can be found at another URL using GET.
Common causes and when you see it
Redirecting after a POST so a refresh does not resubmit the form.
How to fix or handle it
Follow the Location header with a GET request.
Test it yourself
Send a request with the online API tester, inspect the response with the HTTP header checker, or host an endpoint that returns 303 with the mock API generator to see how your app reacts.
HTTP 303 questions
The response to the request can be found at another URL using GET.
Redirecting after a POST so a refresh does not resubmit the form.
Follow the Location header with a GET request.