Alpaca Trading API
REST API for commission-free stock, ETF, and crypto trading, including market data, account management, and order management for algorithmic and agent-based trading strategies.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
FINRA/SEC regulated. API key + secret in headers. No scope granularity - trading and account access on same key. client_order_id provides idempotency. Separate paper/live credentials reduce live trading risk.
⚡ Reliability
Best When
You're building algorithmic trading strategies and want a commission-free, developer-friendly API for stocks and crypto.
Avoid When
You need multi-broker routing, advanced options strategies, or institutional-grade execution quality.
Use Cases
- • Algorithmic trading with programmatic order placement and portfolio management
- • Real-time market data streaming for agent decision-making
- • Paper trading for AI strategy testing before live deployment
- • Account balance, position, and order history monitoring
- • Fractional share trading for dollar-cost averaging strategies
Not For
- • Non-Alpaca brokerage accounts
- • Complex multi-leg options strategies requiring sophisticated execution
- • Ultra-high-frequency trading
Interface
Authentication
API key and secret key pair passed in headers (APCA-API-KEY-ID and APCA-API-SECRET-KEY). Separate paper and live trading credentials.
Pricing
Agent Metadata
Known Gotchas
- ⚠ Paper and live endpoints have different base URLs - easy to mix up
- ⚠ Market data has separate subscription tiers (free vs paid feed); free tier has 15-min delay
- ⚠ Order fills are asynchronous - must poll or use WebSocket for fill confirmation
- ⚠ Fractional shares have different minimum amounts than whole share orders
- ⚠ PDT rule (Pattern Day Trader) applies to accounts under $25k - agents must track day trades
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Alpaca Trading API.
Scores are editorial opinions as of 2026-03-06.