What it does
Alpaca provides APIs for market data, personal trading applications and embedded brokerage. Trading API serves individual-account automation; Broker API supports businesses building investing into their products. Developers can begin with a free paper account before considering live-account permissions.
A research notebook, a personal trading bot and a customer-facing brokerage app have different needs. Start with Trading API for your own application and Broker API for embedded customer accounts. Data subscriptions are a separate choice from permission to place live orders.
Develop in the paper environment
Anyone can create a Paper Only account with an email address. Use that account’s API key and paper endpoint, then inspect simulated activity and balances in the web dashboard. The key is different from a live account’s key. To begin a fresh simulation, choose the account number and Open New Paper Account. Simulated orders are not sent to an exchange.
Basic market data is free: real-time equity coverage is IEX, streaming is limited to 30 symbols, and historical requests allow 200 calls per minute with the latest 15 minutes restricted. Algo Trader Plus costs US$99 monthly, adds all US stock exchanges, removes that recent-history restriction and allows 10,000 historical calls per minute. Broker-partner subscriptions have separate terms.
Strengths
- Paper Only accounts let developers test without opening live trading access
- Trading API and Broker API separate personal tools from embedded customer products
Watch out for
- Basic real-time equity data covers IEX rather than all US exchanges
- Paper simulations do not reproduce every live execution condition
Best for
- Developers prototyping market-data and trading applications
- Businesses evaluating embedded brokerage infrastructure
Sources
- Alpaca developer and embedded investing catalogue (Oct 27, 2026)
- Alpaca Trading API market-data subscription limits (Oct 27, 2026)
- Alpaca paper-account access, keys and simulation controls (Oct 27, 2026)