const options = {method: 'GET', headers: {Authorization: 'Basic <encoded-value>'}};

fetch('https://api.opereit.ai/v1/contracts', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "data": [
    {
      "id": "<string>",
      "carrier_name": "DHL Express",
      "signing_date": "2023-12-25",
      "status": "PROCESSING",
      "rate_count": 123,
      "surcharge_count": 123,
      "created_at": "2023-11-07T05:31:56Z",
      "contract_number": "<string>",
      "account_number": "<string>",
      "effective_date": "2023-12-25",
      "expiration_date": "2023-12-25",
      "status_reason": "<string>",
      "file_url": "<string>"
    }
  ],
  "pagination": {
    "cursor": "<string>",
    "has_more": true
  }
}

{
  "statusCode": 401,
  "statusReasonCode": "AUTHENTICATION_REQUIRED",
  "error": "Authentication required"
}