How to assign a transporter for a 3rd party fulfillment order?

Hi Team,

We would like to understand the process of assigning transporter/carrierservice for an fulfillment order from 3rd party fulfillment.

We have used the fulfillment event api to update the status with “ready_for_pickup” and we see the fulfillment payload is updated with shipment status =‘ready_for_pickup’. Please find the below request and response.

Request Body

{“event”:
{“status”:“ready_for_pickup”,
“order_id” : “4440521343155”,
“fulfillment_id” : “3961761136819”}
}

Response :
{
“fulfillment_event”: {
“id”: 17912511070387,
“fulfillment_id”: 3961761136819,
“status”: “ready_for_pickup”,
“message”: null,
“happened_at”: “2022-07-20T18:31:40+05:30”,
“city”: null,
“province”: null,
“country”: null,
“zip”: null,
“address1”: null,
“latitude”: null,
“longitude”: null,
“shop_id”: 53677686963,
“created_at”: “2022-07-20T18:31:40+05:30”,
“updated_at”: “2022-07-20T18:31:40+05:30”,
“estimated_delivery_at”: null,
“order_id”: 4440521343155,
“admin_graphql_api_id”: “gid://shopify/FulfillmentEvent/17912511070387”
}
}

If we can get on a call and understand the transporter assignment process would be much appreciated.