AWS Api Gateway not accepting OPTIONS with fetch while axios works fine

Question

AWS API Gateway sending 403 error on OPTIONS request for GET api call using fetch with below details from fiddler:

HTTP/1.1 403 Forbidden
Date: Fri, 23 Sep 2022 11:50:57 GMT
Content-Type: application/json
Content-Length: 42
Connection: keep-alive
x-amzn-RequestId: 02883556-5b3b-4af7-8c3a-3d561f2e0557
x-amzn-ErrorType: MissingAuthenticationTokenException
x-amz-apigw-id: Y6WFM7rPEF9iQ=

{"message":"Missing Authentication Token"}

While same url works fine with Axios request with exact request details verified by fiddler.

Answer 1

Fetch request was missing mode property, it defaults to no-cors that does not allow option request, setting mode to cors worked.

return fetch(`${process.env.URL}edit_session/${documentId}?${new URLSearchParams({
                edit_token: editToken,
                action: 'clear'
            })}`, {
                method: 'GET',
                keepalive: true,
                headers,
                mode: 'cors',
                cache: 'no-cache'
            });