payload.json

{
    "type": "email",
    "subject": "Email Case Subject",
    "priority": 4,
    "status": "open",
    "labels": [
        "Spam",
        "Ignore"
    ],
    "message": {
        "direction": "in",
        "body": "Example body",
        "to": "someone@desk.com",
        "from": "someone-else@desk.com",
        "subject": "My email subject"
    },
    "_links": {
        "customer": {
            "class": "customer",
            "href": "/api/v2/customers/1"
        }
    }
}