payload.json

{
    "channel": "ABCDEBF1",
    "attachments": 
    [
        {
            "mrkdwn_in": ["text"],
            "color": "#36a64f",
            "pretext": "Optional pre-text that appears above the attachment block",
            "author_name": "author_name",
            "author_link": "http://flickr.com/bobby/",
            "author_icon": "https://placeimg.com/16/16/people",
            "title": "title",
            "title_link": "https://api.slack.com/",
            "text": "Optional `text` that appears within the attachment",
            "fields": 
            [
                {
                    "title": "A field's title",
                    "value": "This field's value",
                    "short": false
                },
                {
                    "title": "A short field's title",
                    "value": "A short field's value",
                    "short": true
                },
                {
                    "title": "A second short field's title",
                    "value": "A second short field's value",
                    "short": true
                }
            ],
            "thumb_url": "http://placekitten.com/g/200/200",
            "footer": "footer",
            "footer_icon": "https://platform.slack-edge.com/img/default_application_icon.png",
            "ts": 123456789
        }
    ]
}