curl --request GET \
  --url https://api.example.com/is-valid-root

const options = {method: 'GET'};

fetch('https://api.example.com/is-valid-root', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "valid": true
}

{
  "message": "<string>"
}