curl --request GET \
  --url https://my.cald.ai/client/api/v1/lists/{listId}/contacts \
  --header 'Authorization: <api-key>'

{
  "contacts": [
    {
      "phoneNumber": "<string>",
      "prospectName": "<string>",
      "email": "<string>",
      "yourCustomVariable": "<string>"
    }
  ]
}