curl -X GET 'https://api.nuntly.com/messages' \
  -H 'Authorization: Bearer apk_xxx'

{
  "data": [
    {
      "id": "<string>",
      "createdAt": "<string>",
      "inboxId": "<string>",
      "threadId": "<string>",
      "messageId": "<string>",
      "from": "<string>",
      "to": [
        "<string>"
      ],
      "cc": "carlo43@gmail.com",
      "bcc": "archive@company.com",
      "replyTo": "support@company.com",
      "subject": "<string>",
      "receivedAt": "<string>",
      "labels": [
        "<string>"
      ],
      "attachmentCount": 123
    }
  ],
  "nextCursor": "<string>"
}