Alpaca is a developer-first, API-native brokerage infrastructure platform that gives algorithmic traders, fintech startups, and institutional firms programmatic access to U.S. stocks, ETFs, options, fixed income, and crypto—all commission-free. Unlike traditional retail brokers, Alpaca is built from the ground up for code: users interact entirely through REST and WebSocket APIs, with official SDKs in Python, JavaScript, Go, and C#. The Trading API serves individual algo traders and quants, while the Broker API enables fintech companies, robo-advisors, and prop-desk operators to embed brokerage services directly into their own products. A paper-trading environment mirrors the live API exactly, allowing strategies to be backtested and validated before capital is deployed.
Key capabilities include commission-free trading with zero per-share fees, fractional share support, 24/5 extended-hours trading, multi-leg options strategies (spreads, straddles, iron condors), and a high-yield cash management account with up to $2.5M FDIC coverage through partner banks. Alpaca's proprietary OMS v2 delivers 1.5ms order processing, and a FIX API was introduced in 2024 for high-frequency institutional clients. The Market Data API offers two tiers: a free Basic plan with IEX quotes and a $99/month Algo Trader Plus plan with full SIP real-time data, unlimited API calls, and real-time options chains.
Founded in 2015 and headquartered in San Mateo, California, Alpaca is backed by Portage Ventures, Spark Capital, Y Combinator, and SBI Holdings. The company raised a $52M Series C in April 2025 and a landmark $150M Series D in January 2026, reaching a $1.15B unicorn valuation after hitting $100M in annualized revenue. Citadel Securities, BNP Paribas, and Kraken are among its backers. BrokerChooser awarded Alpaca Best Broker for Algorithmic Trading in 2026—a recognition of its growing dominance in programmable brokerage infrastructure.