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Commission-free stock trading API for developers
Alpaca is a technology platform that provides commission-free stock and crypto trading APIs for developers, enabling fintech companies, robo-advisors, and financial apps to offer trading capabilities without building broker-dealer infrastructure. Founded in 2015 and backed by Y Combinator and others, Alpaca has become the go-to platform for developers building trading applications. The Trading API provides programmatic access to buy, sell, and manage positions in US equities and cryptocurrencies with paper trading for testing. Market Data API delivers real-time and historical bars, quotes, trades, and snapshots for US equities from all major exchanges. Broker API enables fintech companies and financial advisors to offer trading to their customers, handling account opening, funding, order management, and reporting. Alpaca's commission-free model is made sustainable by payment for order flow and interest income. The platform supports fractional shares, enabling investment in any amount. Streaming WebSocket APIs provide real-time market data and order status updates. SDKs for Python and JavaScript are well-maintained with active open-source communities. Alpaca's developer community is particularly strong in the algorithmic trading space, with many open-source strategy libraries built on top of Alpaca's APIs. The paper trading environment faithfully replicates live trading mechanics. Alpaca serves thousands of individual developers and hundreds of fintech companies building automated trading and investment applications.