sample_post.json

{
  "object":"page",
  "entry":[
    {
      "id": "PAGE_ID",
      "time":1457764198246,
      "messaging":[
        {
          "sender":{
            "id":"USER_ID"
          },
          "recipient":{
            "id":"PAGE_ID"
          },
          "timestamp":1457764197627,
          "message":{
            "mid":"mid.1457764197618:41d102a3e1ae206a38",
            "seq":73,
            "text":"hello, world!"
          }
        }
      ]
    }
  ]
}