Alpaca
Markets
Commission-free US stocks, options, and crypto brokerage API with a free paper-trading environment
MCPllms.txt
API keyfree
A directory of services AI agents can actually use — APIs, tools and merchants with machine-readable interfaces and agent payment protocols. Badges are probe-backed, never self-asserted.
Markets
Stocks, options, forex, and crypto market data over REST and WebSocket, with a free self-serve API key
Same query as JSON: /api/v1/services?category=markets&has_llms_txt=true