Environment
Language
Javascript - Node.js
Alpaca SDK Version
@alpacahq/alpaca-trade-api: 4.0.2
Other Environment Details
I’m testing a bot locally first
Problem
Summary
I’m testing market orders on my paper account via alpaca.trading.submitAndWait() (Node SDK 4.0.2), one minute after the open (09:31 ET).
Order ID: 2d8e23d6-0fcb-441e-bc90-65a195b71047: buy 5 NVDA, type market, TIF day.
Timeline from the trade_updates stream (UTC):
- 13:31:01.181: created /
pending_new - 13:31:02.276:
new - 13:32:26.843:
partial_fill, 4 @ 230.52 (85s after submission) - 13:33:07.328:
fill, 1 @ 230.21 (126s after submission)
All timestamps are from Alpaca’s servers, so the delay is entirely internal. For a 5-share market order on a highly liquid stock like NVDA, I’d expect the simulator to fill almost immediately at the current quote. Instead, the first fill came 85 seconds after the order was accepted, and the full fill took another 41s to complete. This means the average fill ended up about $1.09 above the price at submission.
Is this expected behavior of the paper engine around the open, or a known issue? Is there a way to get realistic market-order fill timing in paper so I can test my execution logic?
Paper or Live Trading?
Paper
Example Code
const entryOrderResponse = await alpaca.trading.submitAndWait({type: 'market', symbol: 'NVDA', side: 'buy', qty: 5}, {timeoutMs: 10000})