OrderUpdatedCopy Anchor Link

OrderUpdated records a change to an order's quantity, price, trigger price, or calculated protection price. The execution pipeline applies it to the order, updates the Cache, and publishes it on the MessageBus. The change can come from a trading venue, simulated matching engine, local order emulator, or reconciliation.

Typical transition: PENDING_UPDATE -> previous status (for example ACCEPTED). Handler: on_order_updated.

ContractCopy Anchor Link

quantity is the order's gross quantity: inclusive of filled quantity and any non-reopened voided quantity (see OrderFillVoided). Nautilus derives working leaves as

leaves_qty = max(quantity - filled_qty - non_reopened_voided_qty, 0)

so a non-reopened void stays excluded from leaves across subsequent updates without adapters having to net it out of quantity themselves. An adapter that reports quantity net of a non-reopened void causes leaves to double-subtract that quantity.

Terminal reconciliation is the exception. A reconciliation update (reconciliation=True) whose quantity equals the order's non-zero filled_qty closes the order as FILLED. Here quantity is the effective filled quantity, net of voided quantity. Thus, an adapter that closes an order at what it filled reports filled_qty rather than the gross quantity.

FieldsCopy Anchor Link

Beyond the common Python order event fields, OrderUpdated carries:

ExampleCopy Anchor Link

Reading the event in a strategy handler:

def on_order_updated(self, event: OrderUpdated) -> None:
    self.log.info(
        f"Order {event.client_order_id} updated: qty={event.quantity} price={event.price}",
    )

Related guidesCopy Anchor Link

• Events - Event categories, dispatch, and the common order event fields.
• Orders - Order types and the state machine.