Execution: venue.trade() in chat code, strategy.execute() in strategy agents.
Overview
Alpaca connects to Scalar Field via OAuth and provides two accounts: ALPACA_PAPER (simulated money) and ALPACA_LIVE (real money). Both support US equities, ETFs, and options, with identical call semantics — strategy code validated on paper runs unchanged against live.
| Specification | Value |
|---|
| Instruments | US equities, ETFs, and options (OPRA/OSI symbols) |
| Accounts | ALPACA_PAPER, ALPACA_LIVE |
| Connection | OAuth |
| Fractional | Yes (equities) |
| Hours | US market hours; off-hours orders queue for the next open |
| Fill model | Asynchronous — orders may return PENDING |
| Quotes | Last, bid, ask, volume (no order-book depth) |
| Currency | USD |
Order Semantics
- Equity symbols are plain tickers (
AAPL); options use OPRA/OSI symbols (AAPL260919C00250000). Option positions carry multiplier: 100, so market_value = qty * price * 100.
- Fills are asynchronous.
venue.trade() may return "PENDING" — the order is submitted but not yet filled. Orders use day time-in-force; orders placed outside market hours remain PENDING until the next open. Pending orders are reconciled automatically (see Reconciliation).
- Fractional quantities are supported for equities. Size from a dollar budget with
round(budget / price, 2).
- The
slippage_bps parameter does not apply to Alpaca.
Connecting
Click “Connect” on the portfolio page and authorize with your Alpaca account. Paper and live accounts link through the same OAuth flow.
Usage
from scalarlib import venue
# Equities on paper
resp = venue.trade("buy", "AAPL", 5, account="ALPACA_PAPER")
# Same call against the live account
resp = venue.trade("buy", "AAPL", 1.5, account="ALPACA_LIVE")
# Options by OPRA symbol
resp = venue.trade("buy", "AAPL260919C00250000", 1, account="ALPACA_PAPER")
strategy.execute(symbol, target_qty) instead — see Strategies.
Data Functions
Equity and options research uses the cross-asset market-data functions; each links to its full reference:
| Function / dataset | Purpose |
|---|
| Equity & ETF OHLCV | Historical price bars for backtesting and signals |
| Latest Price Snapshot | Live last/bid/ask quotes for sizing and execution checks |
| Options Quotes | Options chains and quotes |
| Options Greeks & IV | Greeks and implied volatility |
| Options Screener | Contract screening by moneyness, expiry, volume |
| Earnings | Earnings calendar and results |
| Insider Trades | SEC Form 4 insider transactions |
| Institutional Holdings | 13F institutional positions |
Notes
- Positions and cash update only on terminal order states (filled, cancelled, expired); partial fills on a live order are not reflected until the order is terminal.
- A
PENDING response outside market hours is normal — the order executes at the next open.
- Avoid trading directly on the Alpaca dashboard while strategies are active on the account — see Reconciliation.
Related
