curl --request POST \
  --url https://api.example.com/packed-account \
  --header 'Content-Type: application/json' \
  --data '
{
  "authenticator_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb"
}
'

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({authenticator_address: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb'})
};

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

{
  "packed_account_data": "0x1"
}

{
  "code": "<unknown>",
  "message": "<string>"
}