Alpaca
API-first broker. Commission-free. Ideal for algo trading (REST + WebSocket API).
Overview
Alpaca Markets, Inc. is an API-first stock brokerage platform founded in 2015 by Yoshi Yokokawa and Hitoshi Harada. Headquartered in San Mateo, California, Alpaca is designed specifically for developers and algorithmic traders who want to build automated trading systems using modern REST and WebSocket APIs.
Alpaca is regulated by the SEC and FINRA and is a member of SIPC. The platform provides commission-free trading in US stocks and ETFs, with a focus on making it easy to integrate trading into software applications. Alpaca is widely used by fintech startups, hedge funds, and individual developers building trading bots.
What makes Alpaca unique in the brokerage space is its developer-first approach. The platform offers comprehensive API documentation, official SDKs in Python, JavaScript, Go, and C#, paper trading for testing, and real-time market data — all designed to make programmatic trading accessible and reliable.
Key Features
- API-first design: Full REST and WebSocket APIs for trading, account management, and market data
- Commission-free trading: $0 for US stock and ETF trades
- Official SDKs: Python (alpaca-py), JavaScript, Go, C# client libraries
- Paper trading: Full simulation environment with same API endpoints
- Real-time market data: Free IEX data, paid SIP consolidated data
- Fractional shares: Trade fractional shares via API
- Crypto trading: BTC, ETH, and 20+ tokens via API
- OAuth integration: Build apps that trade on behalf of users (Broker API)
- Broker API: White-label brokerage for fintech companies
Supported Markets
| Market Type | Details | |-------------|---------| | Stocks | US stocks on NYSE, NASDAQ via API | | ETFs | Commission-free ETF trading via API | | Crypto | BTC, ETH, and 20+ tokens via API | | Fractional Shares | Minimum $1 or 0.001 shares |
Fee Structure
| Type | Fee | |------|-----| | US Stocks & ETFs | $0 commission | | Crypto | Varies (spread-based) | | Market Data (IEX) | Free | | Market Data (SIP) | $9/month (individuals) | | Account minimum | $0 | | API access | Free | | Paper trading | Free |
Platforms & Interfaces
- REST API: Full trading, account, portfolio, and order management endpoints
- WebSocket: Real-time streaming for market data and order updates
- alpaca-py: Official Python SDK for trading and data
- Web Dashboard: Basic account management and monitoring at app.alpaca.markets
- Paper Trading: Identical API with simulated execution
Regulation
- SEC / FINRA (United States)
- SIPC member — up to $500,000 protection
- Self-clearing broker-dealer
Getting Started
- Sign up at alpaca.markets for a free account
- Generate API key and secret from the dashboard
- Install the SDK:
pip install alpaca-py(Python) - Start with paper trading to test your strategies
- Switch to live trading when ready (identity verification required)