Massive (formerly Polygon.io) MCP server
Search and call the whole Massive.com market-data API — stocks, options, forex, crypto, futures, fundamentals, news — and run SQL over the results in a scratch in-memory table.
Install
-
Install (pinned)
uv tool install "mcp_massive @ git+https://github.com/massive-com/mcp_massive@v0.10.0" -
Claude Code
claude mcp add massive -e MASSIVE_API_KEY=your_api_key_here -- mcp_massive
Polygon.io renamed itself Massive in October 2025; this is its official MCP server. Instead of
one tool per endpoint it exposes three: search_endpoints to find the right API call,
call_api to run it (optionally saving the result as a table), and query_data to run SQL over
saved tables. Built-in functions add Black-Scholes prices and greeks, returns, Sharpe and Sortino
ratios, and simple and exponential moving averages.
When to use it
- Multi-step market analysis: pull several series, join them, compute returns — all in one session.
- Options work where you want greeks computed next to the chain data.
- You’re already a Polygon/Massive customer.
Before you install
The README marks the project experimental and subject to breaking changes; pin the tag. The free “Stocks Basic” plan allows 5 calls a minute and end-of-day data; most useful data needs a paid plan. The old POLYGON_API_KEY variable still works but is deprecated. Saved tables live in memory and expire after an hour.
Limits
The built-in finance functions are computed on whatever data was fetched; the model still chooses the inputs and can pick the wrong series or window. Check results before relying on them. Not investment advice.
- Publisher
- Massive
- Works with
- Claude apps, Claude Code, Any agent
- Categories
- Investment analysis, MCP & integrations, Market data
- License
- MIT
- Cost
- Free tier, paid plans