curl -X POST 'https://api.sendforsign.com/api/placeholder' \ 
     -H 'X-Sendforsign-Key: YOUR_API_KEY' \
     -H 'Content-Type: application/json' \
     -d '{ 
          "data": {
              "action": "list",
              "clientKey": "YOUR_CLIENT_KEY",
              "contractKey": "CONTRACT_KEY",
              "templateKey": "TEMPLATE_KEY"
				  }
     }'

{
    "placeholders": [
        {
            "id": "1",
            "createTime": "2024-02-26T11:07:55.000Z",
            "changeTime": "2024-02-26T11:07:59.000Z",
            "name": "Placeholder Name",
            "value": "Placeholder Value",
            "placeholderKey": "PLACEHOLDER_KEY",
            "position": 1
        }
    ],
    "code": "200",
    "message": "Placeholders found"
}