How to update (replace) existing order multiple times

Alpaca Products Discussion
1

Frequently, I need to update an initial order multiple times, mostly to catch up with a fast moving market. For the life of me I could not figure out how exactly the update mechanism works in Alpaca. It seems convoluted!

(In another API you would simply send a new limit price with existing order_id and that would be that)

Here are the steps I moved through. Could anyone please fill the rest in the rest?

  1. api.submit_order(), returns Order object with “order_id_1”, “client_order_id_1”, status ACCEPTED

  2. channel trade_updates receives order dictionary with “order_id_1”, “client_order_id_1”, status NEW

– time passes suppose the order does not fill or cancel

  1. api.replace_order(“order_id_1”, new_price) returns “order_id_2”, “client_order_id_2”, status ACCEPTED ?

  2. channel trade_updates receives order dictionary with “order_id_2”, “client_order_id_2”, status REPLACED

price moves fast, no fill, I want to update the order again

  1. api.replace_order(“order_id_2”, new_price) returns error “… order in replaced status cannot be changed…”
2

OK - spent more time with paper trading than I would have liked and figured how it works.

When you call

new_order = api.replace_order(order_to_update)

it returns a new order object, with a new unique order_id and order_client_id. Stick to these new ids, as you will refer to your updated order with these. Then a trade_update arrives with status=REPLACED and (order_id, client_order_id) of the ‘order_to_update’. This is formal confirmation that the update executed, you can now safely discard your order_to_update object, if you have not already done so.

Another little thing that threw me off when receiving trade_updates is that, the data.order field that arrives is a dictionary, whereas placing an order returns an object. I wish they were both either dictionary or preferably object. Two different implementations for the same concept. Well, at least the field names are the same.

3

@ Trader Joe,
I am not able to replace the order as well.
Please elaborate on the order_to_update item and an example with steps.
Rest object looks like it should be straight forward, but it is not.
Thanks

4

Ok got it working. As Trader Joe mentioned, every order replacement will create a new client id. Although i didn’t see order_id change. So if your replace_order call has client id filled up, it will throw an error. Here is an example of what I use, and it worked. One pointer though, if using time_in_force make sure it is accepted condition for original order, for example changing ‘day’ to ‘opg’ on extended hours order will result in an error.
api.replace_order(order.id,qty,close_price)

Thanks

5

Is there a way to omit qty from replace_order and just replace the order for the remaining unfilled qty?

6

Suggest to pull it from order if you don’t want to update it, like below,

open_orders = api.list_orders()
for order in open_orders:
    if order.symbol == your_stock:
            api.replace_order(order.id,order.qty,new_price)
7

This might work only if the order is on the exchange, i don’t know why we can’t change orders if are not on the exchange:

APIError: unable to replace order, order isn't sent to exchange yet