curl --request GET \
  --url https://app.herondata.io/api/end_users/{end_user_id_or_heron_id}/missing_accounts \
  --header 'x-api-key: <api-key>'

{
  "missing_accounts": [
    {
      "account_name": "Checking",
      "account_number": "****4321",
      "transactions": [
        {
          "amount": -42.42,
          "description": "GOOGLE *ADS12340929 [email protected] US",
          "account_id": "checking_account_202348",
          "currency": "USD",
          "heron_id": "txn_kebhhtRg7eR4bZ5hjXHGhf",
          "timestamp": "2021-11-12T10:38:05Z"
        }
      ]
    }
  ]
}