Fetch -API returning HTML instead of JSON

Header is not correct. Valid header for JSON response:

headers: {    'Accept': 'application/json',    'Content-Type': 'application/json',  }

javascript json fetch-api

Sometimes Apis return html instead of json if you are not logged in, confirm that as well

javascript json fetch-api

Also double check you have selected the correct HTTP method in the dropdown box, next to the input bar on postman.

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