Signal8 API & MCP Server Reviews & Product Details

Signal8 API & MCP Server gives developers, fintech teams and research firms structured SEC filing and market data for US-listed stocks, with a focus on small caps. Data includes insider Form 4 trades, congressional STOCK Act trades, 13F institutional holdings, dilution data (warrants, convertibles, shelf registrations and ATM offerings), trading halts, reverse splits, short interest and quotes. There are two ways in: a REST API with API keys, or a hosted MCP server (https://mcp.signal8.ai/mcp, also on npm as @signal8ai/mcp) that connects Claude, ChatGPT, Cursor, VS Code and other MCP clients to the same data. API and MCP access are included in Signal8 Pro, at 120 requests per minute, 10,000 requests per day and 3 API keys. The free Signal8 Academy tools in the MCP server work without a key. Built by Signal8 Inc., founded in 2025 and based in Sheridan, Wyoming.