const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

fetch('https://sandbox.api.enfinitos.com/v1/healthz', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "ok": true,
  "data": {},
  "contractVersion": "<string>"
}