alpaca-py

What it is and what it does

Alpaca-py is the official Python SDK that wraps Alpaca's REST, WebSocket, and SSE APIs into a unified, object-oriented interface. It lets you build trading applications, stream live market data, and manage brokerage accounts programmatically. The library uses pydantic for runtime data validation and provides separate client classes for different asset classes and API products—TradingClient for orders, StockHistoricalDataClient for historical data, BrokerClient for account management, and specialized data stream clients for real-time feeds.

The package depends on msgpack, pandas, pydantic, pytz, requests, sseclient-py, and websockets to handle serialization, data frames, validation, time zones, HTTP requests, server-sent events, and WebSocket connections. It's designed for developers building algorithmic trading strategies, robo-advisors, or full brokerage experiences. Request models (e.g., MarketOrderRequest, CryptoBarsRequest) enforce schema validation before sending to Alpaca's servers, reducing runtime errors.

Use it for:

• Build algorithmic trading strategies that automatically submit orders and stream live market data for stocks, crypto, or options.
• Create a robo-advisor or investment app that manages multiple brokerage accounts under your control via the Broker API.
• Backtest trading strategies using historical bar data from Alpaca's market data API for multiple asset classes.
• Stream real-time market data (quotes, bars, trades) via WebSocket or SSE for live dashboards or monitoring systems.
• Validate and parse trading order data from JSON payloads using pydantic-backed request models before execution.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Alpaca-py is the official Python SDK for interacting with Alpaca's trading, market data, and broker APIs, supporting REST, WebSocket, and SSE endpoints for stock, crypto, and options trading and data access.

Yes. Alpaca-py is actively maintained, has no known vulnerabilities, low install friction, and a permissive license. It is the official SDK for Alpaca's APIs and is well-suited for anyone building trading or investment applications that need to interact with Alpaca's services. The OOP design and pydantic validation reduce errors compared to raw HTTP calls.

Install

alpaca-py on PyPI

pip install alpaca-py

uv add alpaca-py

poetry add alpaca-py

Installing alpaca-py

Before you install

Low install friction with a pure-Python wheel distribution. Actively maintained with a recent release (3 days old) and steady repository activity. Supports Python 3.10 through 3.14.

License in practice

Apache-2.0 is permissive; you can use, modify, and distribute alpaca-py freely in commercial or private projects with minimal restrictions.

Quickstart

pip install alpaca-py

from alpaca.trading.client import TradingClient
from alpaca.trading.requests import MarketOrderRequest
from alpaca.trading.enums import OrderSide, TimeInForce

trading_client = TradingClient('api-key', 'secret-key')
order = trading_client.submit_order(
    MarketOrderRequest(
        symbol="BTC/USD",
        qty=0.0001,
        side=OrderSide.BUY,
        time_in_force=TimeInForce.DAY
    )
)

Requires an Alpaca account and API keys (trading, market data, or broker keys depending on which APIs you use); Python 3.10 or later.

Verify before relying

• Specific latency or throughput characteristics of WebSocket and SSE streaming connections.
• Whether all asset classes (stocks, crypto, options) are equally mature or if some are newer.
• Real-world performance under high-frequency trading or large data volume scenarios.

Package facts

Evidence: alpaca_py-0.44.0-py3-none-any.whl

Tags

More WWW/HTTP packages