When transaction is success, you will get "status": "paid" AND "status_transitions.paid" : 1588688731.

response.json

{
    "type": "success",
    "code": 200,
    "data": {
        "id": "or_1GfRiABkM3dAaKZOJIr63AuR",
        "object": "order",
        "amount": 2799,
        "amount_returned": null,
        "application": null,
        "application_fee": null,
        "charge": "ch_1GfRiABkM3dAaKZO8OA3VCTL",
        "created": 1588688730,
        "currency": "usd",
        "customer": null,
        "email": "chanu1993@gmail.com",
        "items": [
            {
                "object": "order_item",
                "amount": 2299,
                "currency": "usd",
                "description": "Demo Product 1",
                "parent": "sku_GXFKpYsKt9nHYZ",
                "quantity": 1,
                "type": "sku"
            },
            {
                "object": "order_item",
                "amount": 0,
                "currency": "usd",
                "description": "Taxes (included)",
                "parent": null,
                "quantity": null,
                "type": "tax"
            },
            {
                "object": "order_item",
                "amount": 500,
                "currency": "usd",
                "description": "For shipping inside US, it will be $5",
                "parent": "ship_CEaTnjGcpGIXRxQQ",
                "quantity": null,
                "type": "shipping"
            }
        ],
        "livemode": false,
        "metadata": {},
        "returns": {
            "object": "list",
            "data": [],
            "has_more": false,
            "total_count": 0,
            "url": "/v1/order_returns?order=or_1GfRiABkM3dAaKZOJIr63AuR"
        },
        "selected_shipping_method": "ship_CEaTnjGcpGIXRxQQ",
        "shipping": {
            "address": {
                "city": "Horana",
                "country": "SL",
                "line1": "No 5B, Polwatta Road",
                "line2": "Gurugoda",
                "postal_code": "12400",
                "state": "Western"
            },
            "carrier": null,
            "name": "Chanaka De Silva",
            "phone": null,
            "tracking_number": null
        },
        "shipping_methods": [
            {
                "id": "ship_CEaTnjGcpGIXRxQQ",
                "amount": 500,
                "currency": "usd",
                "delivery_estimate": null,
                "description": "For shipping inside US, it will be $5"
            }
        ],
        "status": "paid",
        "status_transitions": {
            "canceled": null,
            "fulfiled": null,
            "paid": 1588688731,
            "returned": null
        },
        "updated": 1588688731
    }
}