Log inSign up
WebSocketStocks & Equities

Alpaca Market Data Streaming (Stocks WebSocket)

Alpaca Market Data Streaming (Stocks WebSocket) is a websocket from Alpaca Markets providing stocks & equities data. Real-time WebSocket stream for US equities delivering trades, quotes, and minute/daily bars. A Polymarket bot can subscribe to a ticker (e.g. TSLA, SPY) to track live price and continuously evaluate "will X close above $Y" equity/index threshold markets with a free IEX-tier feed.

At a glance

ProviderAlpaca Markets
TypeWebSocket
CategoryStocks & Equities
Real-timeYes — streaming
AuthAPI key
PricingFree IEX real-time tier; paid Algo Trader Plus (full SIP) from $99/mo — Free ($0/mo): real-time IEX WebSocket, up to 30 streaming symbols, 200 REST calls/min, 7+ yrs history (REST 15-min delayed for SIP), Algo Trader Plus ($99/mo): full SIP real-time from all US exchanges, unlimited WebSocket symbols, up to 10,000 calls/min, real-time OPRA options

What data it provides

  • Real-time trades (price, size, exchange, conditions)
  • Real-time quotes (bid/ask price and size)
  • Minute aggregate bars (OHLCV) and daily bars
  • Updated/corrected trade and bar messages
  • Streaming news headlines and crypto/options feeds (separate channels)
  • Test stream symbol FAKEPACA available outside market hours

Features

  • Free tier IEX feed real-time over WebSocket; SIP (full-market) requires paid plan
  • Subscription channel model: subscribe to trades/quotes/bars per symbol or wildcard '*'
  • Free tier capped at 30 streaming symbols; unlimited symbols on Algo Trader Plus
  • Endpoint wss://stream.data.alpaca.markets/v2/{feed} (iex or sip); sandbox host available
  • 7+ years of historical data via companion REST API for backfill
  • Official SDKs: alpaca-py (Python), alpaca-trade-api, plus Go/Node/C# community libs

Links

Use it in a bot

Other stocks & equities data sources

Listed, not endorsed. Pricing and capabilities change without notice — check the provider's own documentation before you depend on anything here. Browse the full data resources directory or the strategy database.
Join Discord