Alpaca
Alpaca is a developer-first, commission-free brokerage that exposes stock, ETF, options, and crypto trading and market data entirely through APIs. The Trading API places and manages orders against a free paper-trading sandbox (paper-api.alpaca.markets) or a live account (api.alpaca.markets/v2); the Market Data API serves historical and real-time stocks, crypto, options, news, and corporate actions over REST plus WebSocket streams (data.alpaca.markets and stream.data.alpaca.markets); and the Broker API lets businesses open and fund end-user brokerage accounts. Authentication uses APCA-API-KEY-ID and APCA-API-SECRET-KEY headers, with OAuth2 available for third-party apps.
APIs
Alpaca Trading API
Commission-free trading of US stocks, ETFs, options, and crypto. Submit, replace, and cancel orders; read account balances, positions, portfolio history, and account activities;...
Alpaca Market Data API
Historical and real-time pricing data for US stocks (SIP and IEX feeds), crypto, and options - bars, trades, quotes, snapshots, auctions, orderbooks, latest values, plus a news ...
Alpaca Market Data Streaming API
Real-time market data over WebSocket. Stocks stream at wss://stream.data.alpaca.markets/v2/{feed} (iex, sip, delayed_sip, test) and crypto at wss://stream.data.alpaca.markets/v1...
Alpaca Broker API
Build brokerage and trading products for end users. Open and manage customer brokerage accounts (KYC/onboarding), move money via ACH and wire transfers, journal cash and securit...
Collections
Alpaca API
OPENPricing Plans
Rate Limits
FinOps
Alpaca Markets Finops
FINOPSEvent Specifications
Alpaca Market Data Streaming (WebSocket)
AsyncAPI 2.6 description of Alpaca's **real-time market data WebSocket API**. Unlike many providers, Alpaca publishes a genuine, documented public WebSocket (`wss://`) surface f...
ASYNCAPI