curl --request POST \
  --url https://my.cald.ai/client/api/v1/lists/{listId}/contacts \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "contacts": [
    {
      "phoneNumber": "<string>",
      "prospectName": "<string>",
      "email": "<string>",
      "yourCustomVariable": "<string>"
    }
  ]
}'

{
  "status": "<string>"
}