Alpaca vs IG

Alpaca's Market Data API v2 delivers realtime and historical quotes, trades, and bars for US equities and ETFs over REST and WebSocket, requiring an Alpaca brokerage/API-key account. The free plan gives 200 API calls/minute with 15-minute-delayed IEX-exchange data and 30-symbol WebSocket streams; the $99/month Algo Trader Plus tier removes the call cap, adds true realtime data from all US exchanges (plus real-time OPRA options quotes), and unlimited streamed symbols. Both tiers include 7+ years of historical data.

IG's trading API layers REST order execution and Lightstreamer-based streaming onto the same CFD, spread-betting, and forex engine behind IG's own platform, authenticated with an API key generated from a live account (a linked demo account then lets you sandbox trades risk-free). There's no separate API fee — access is included with any account and gated only by IG's standard per-key usage quotas, not a metered price. A live probe of the real API host (api.ig.com) returned `Access-Control-Allow-Origin: *` even on an error response, confirming CORS is open — correcting the previously-recorded `unknown`.