curl --request GET \
  --url https://api.cleartalk.ai/contacts/{id} \
  --header 'x-api-key: <api-key>'

{
  "id": 123,
  "userId": 123,
  "listName": "<string>",
  "tag": "<string>",
  "firstName": "<string>",
  "lastName": "<string>",
  "email": "<string>",
  "phone": "<string>",
  "dateOfBirth": "<string>",
  "contactSource": "<string>",
  "clearTalkNotes": "<string>",
  "customField": {},
  "createdAt": "2023-11-07T05:31:56Z",
  "updatedAt": "2023-11-07T05:31:56Z"
}