How to add Polygon.io MCP Server to Claude Desktop

Official Polygon.io server with tools for stocks, options, forex, and crypto market data. Paste the config into ~/Library/Application Support/Claude/claude_desktop_config.json and restart Claude Desktop.

Last updated June 15, 2026 · 360★ · stdio · apikey · official

Claude Desktop config for Polygon.io MCP Server

uvx --from git+https://github.com/polygon-io/mcp_polygon@v0.4.0 mcp_polygon

{
  "mcpServers": {
    "polygon-io-mcp-server": {
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/polygon-io/mcp_polygon@v0.4.0",
        "mcp_polygon"
      ],
      "env": {
        "POLYGON_API_KEY": "<your-polygon-api-key>"
      }
    }
  }
}

Requires `uv` (the Python package runner). Install it from https://docs.astral.sh/uv/ if `uvx` is not found.

Setup steps

1Open Claude Desktop → Settings → Developer → Edit Config (this opens ~/Library/Application Support/Claude/claude_desktop_config.json).
2Paste the Polygon.io MCP Server config below under the top-level "mcpServers" key.
3Fill in any placeholder secrets (API keys, paths) in the snippet.
4Save the file, then fully quit and reopen Claude Desktop.
5Open a chat and confirm Polygon.io MCP Server's tools appear under the 🔌 tools menu.

Before you start

A Massive.com (formerly Polygon.io) API key from massive.com — set as MASSIVE_API_KEY (legacy POLYGON_API_KEY also accepted)
Python 3.12 or higher
Astral uv 0.4.0+ to install and run the server

What Polygon.io MCP Server can do in Claude Desktop

search_endpoints

Discover the right Massive/Polygon REST endpoints and built-in functions from a natural-language query.

call_api

Execute any Massive/Polygon REST endpoint, with optional storage of the response into a local SQLite database.

query_data

Run SQL queries against data previously stored by call_api.

Built-in functions (Black-Scholes Greeks, returns, moving averages, ratios)

Analytics helpers callable through the API layer — e.g. options delta/gamma/theta/vega/rho and return calculations.

Security

Read-only market data with no trading capability; keep POLYGON_API_KEY in env. Pin the git tag (e.g. @v0.4.0) rather than tracking main so you run reviewed code.

Polygon.io MCP Server + Claude Desktop FAQ

Where is the Claude Desktop config file?

Claude Desktop reads MCP servers from ~/Library/Application Support/Claude/claude_desktop_config.json. Paste the Polygon.io MCP Server config there under the "mcpServers" key and restart the client.

Is Polygon.io MCP Server safe to use with Claude Desktop?

Read-only market data with no trading capability; keep POLYGON_API_KEY in env. Pin the git tag (e.g. @v0.4.0) rather than tracking main so you run reviewed code.

Why does the package say Massive.com instead of Polygon.io?

Polygon.io rebranded to Massive.com on Oct 30, 2025. The repo and package moved to massive-com/mcp_massive, but it is the same official server and data.

Does my existing Polygon API key still work?

Yes. Existing keys, accounts, and api.polygon.io continue to work, and POLYGON_API_KEY is accepted as a deprecated alias for MASSIVE_API_KEY.

Why only three tools?

The server uses a composable design — search_endpoints, call_api, and query_data — that together cover the entire REST API surface instead of one tool per endpoint.

View repo Full Polygon.io MCP Server page