Stop loss PnL amount

Use the Stop loss PnL amount field to set a portfolio loss cap in dollars. TradersPost converts that cap into a stop price using the quantity calculated for the planned entry before the order is sent to the broker, and the symbol's point value from the quote (for example, dollar value per price point for futures, or the options contract multiplier - 100 per contract for standard equity options).

PnL-based stop loss applies to stop market and stop limit stops. It is not used for trailing stop orders, and it does not apply when you size risk using risk dollar amount or risk percent (those modes use a different sizing path).

From your webhook, use stopLoss.pnlAmount:

{
    "ticker": "AAPL",
    "action": "buy",
    "orderType": "limit",
    "limitPrice": 100,
    "stopLoss": {
        "type": "stop",
        "pnlAmount": 100
    }
}