Alpaca vs Interactive Brokers

Feature Comparison

Feature Alpaca Interactive Brokers
Asset classes US stocks, ETFs Stocks, options, futures, forex, bonds, global markets
Markets US only 150+ markets in 33 countries
Commission $0 stocks Tiered (low per-share)
API style REST + WebSocket Socket-based (TWS API / ib_async)
Latency ~50-100ms ~1-10ms (local gateway)
Paper trading Built-in Requires paper account setup
Data included Free real-time US equities Requires market data subscriptions
Setup complexity API keys only Gateway/TWS installation + config
Minimum account $0 $0 (varies by product)

When to Use Each

Choose Alpaca When

  • You trade US stocks and ETFs only
  • You want the simplest setup (API keys, no gateway)
  • You need free real-time data
  • You’re getting started with algorithmic trading

Choose IBKR When

  • You need options, futures, or forex
  • You trade international markets
  • You need lowest latency (local gateway)
  • You want the widest product selection
  • You need advanced order types (bracket, OCA, etc.)

Side-by-Side Code

Both brokers share the same Broker interface. Swapping is a one-line change:

Setup 

# Alpaca
from puffin.broker import AlpacaBroker
broker = AlpacaBroker(paper=True)

# IBKR
from puffin.broker import IBKRBroker
broker = IBKRBroker(port=4002, paper=True)

Submit an Order 

from puffin.broker import Order, OrderSide, OrderType

order = Order(symbol="AAPL", side=OrderSide.BUY, qty=100, type=OrderType.MARKET)

# Identical call for both brokers
order_id = broker.submit_order(order)

Check Positions 

# Identical for both
positions = broker.get_positions()
for symbol, pos in positions.items():
    print(f"{symbol}: {pos.qty} shares @ ${pos.avg_price:.2f}")

Account Info 

# Identical for both
account = broker.get_account()
print(f"Equity: ${account.equity:,.2f}")
print(f"Buying power: ${account.buying_power:,.2f}")

Data Provider Comparison 

# Alpaca
from puffin.data.alpaca_provider import AlpacaProvider
data = AlpacaProvider()

# IBKR
from puffin.data import IBKRDataProvider
data = IBKRDataProvider(port=4002)

# Same interface
df = data.fetch_historical("AAPL", start="2025-01-01", interval="1d")
Feature AlpacaProvider IBKRDataProvider
Assets US stocks, ETFs Stocks, futures, forex, options
Real-time WebSocket bars 5-second real-time bars
Auth API key env vars Local gateway connection
Free data Yes Requires subscriptions

Migration Guide

Thanks to the shared Broker and DataProvider interfaces, migrating between brokers requires minimal changes:

  1. Change the import and constructor — one line each
  2. Environment setup — Alpaca needs API keys; IBKR needs Gateway running
  3. Everything else stays the same — orders, positions, account info all use identical methods
# Before (Alpaca)
from puffin.broker import AlpacaBroker
broker = AlpacaBroker(paper=True)

# After (IBKR) — only this line changes
from puffin.broker import IBKRBroker
broker = IBKRBroker(port=4002, paper=True)

# All downstream code is unchanged
order_id = broker.submit_order(order)
positions = broker.get_positions()
account = broker.get_account()

For IBKR-specific features (options, futures, forex), use submit_order_with_spec() with a ContractSpec — see IBKR Advanced Trading.

Source Code

Browse the implementation: puffin/broker/