5 Common IBridgePy Mistakes and How to Fix Them

The article “5 Common IBridgePy Mistakes and How to Fix Them” was originally published on IBridgePy blog.

The author of this article is not affiliated with Arclight Capital. This software is in no way affiliated, endorsed, or approved by Arclight Capital or any of its affiliates. It comes with absolutely no warranty and should not be used in actual trading unless the user can read and understand the source. The ARC API team does not support this software.

Avoid These Pitfalls in Your Python Trading Strategy
After helping thousands of traders deploy algorithmic trading strategies with Arclight Capital, we have compiled the most common mistakes that IBridgePy users encounter. Each issue below includes the wrong approach, why it fails, and the correct solution.

Mistake #1: Using time.sleep() to Wait for Order Fills

The wrong way:

order_id = order(symbol('AAPL'), 100)
time.sleep(5)  # Hope it fills in 5 seconds
fill_price = get_order(order_id).avgFillPrice  # Often returns None

Why it fails: time.sleep() blocks the thread without processing incoming IB messages. The fill confirmation sits unprocessed in the message queue.

The fix:

order_id = order(symbol('AAPL'), 100)
order_status_monitor(order_id, 'Filled', waitingTimeInSeconds=30)
fill_price = get_order(order_id).avgFillPrice  # Always populated

Mistake #2: Placing Orders in initialize()

The wrong way:

def initialize(context):
    order(symbol('AAPL'), 100)  # Fails silently

Why it fails: The initialize() function runs before the connection to IB is fully established. Orders must be placed in handle_data() or in a scheduled function.

The fix:

def initialize(context):
    context.ordered = False

def handle_data(context, data):
    if not context.ordered:
        order(symbol('AAPL'), 100)
        context.ordered = True

Mistake #3: Not Handling the “Filled” Status for Market Orders

The wrong way:

order_id = order(symbol('AAPL'), 100)
order_status_monitor(order_id, 'Submitted', waitingTimeInSeconds=30)
# Proceeds without knowing if order actually filled

Why it fails: For market orders, “Submitted” means the order reached IB, not that it executed. A fast-moving market could leave your strategy in an uncertain state.

The fix:

order_id = order(symbol('AAPL'), 100)
order_status_monitor(order_id, 'Filled', waitingTimeInSeconds=30)

For limit orders that may not fill immediately, monitor multiple statuses:

order_status_monitor(order_id, ['Filled', 'Submitted'], waitingTimeInSeconds=30)

Mistake #4: Using get_open_orders() to Check if a Position Was Entered

The wrong way:

# Check if my order filled
open_orders = get_open_orders()
if my_order_id not in open_orders:
    print('Must have filled!')  # Not necessarily true

Why it fails: An order can be absent from get_open_orders() for multiple reasons: it could be filled, cancelled, or rejected. Absence does not confirm a fill.

The fix:

order_obj = get_order(my_order_id)
if order_obj.status == 'Filled':
    print(f'Filled at {order_obj.avgFillPrice}')
elif order_obj.status == 'Cancelled':
    print('Order was cancelled')

Mistake #5: Running Heavy Computation Inside handle_data()

The wrong way:

def handle_data(context, data):
    # This blocks IB message processing for 30 seconds
    result = run_ml_model_on_5000_tickers()
    if result.signal:
        order(symbol('AAPL'), 100)

Why it fails: While handle_data() is blocked by heavy computation, IB callbacks are not being processed. This can cause missed price updates, stale data, and connection timeouts.

The fix: Pre-compute signals before market hours using schedule_function(), or move heavy computation to a separate process and communicate via a file or database:

def initialize(context):
    schedule_function(compute_signals,
                      time_rule=time_rules.spot_time(hour=9, minute=25))

def compute_signals(context):
    # Run before market open
    context.signal = run_ml_model_on_5000_tickers()

def handle_data(context, data):
    if context.signal:
        order(symbol('AAPL'), 100)

Bonus: Enabling Debug Logging

When troubleshooting any issue, enable IBridgePy’s debug output by setting the log level in your settings.py:

logLevel = 'DEBUG'

This reveals the raw IB callback messages and helps identify exactly where communication breaks down.

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