underdog-api-mcp

An MCP server (stdio) for Underdog API: Underdog Fantasy pick'em lines with separate Higher and Lower payout multipliers, recorded line moves, the board at past instants, graded results and hit rates, as tools for Claude, ChatGPT, Cursor, VS Code and any MCP client. No dependencies; Node 18+.

A hosted server with the same data runs at https://underdogapi.com/api/mcp (Streamable HTTP, bearer key). Use this package when your client only speaks stdio or you want the key kept in a local environment variable.

Underdog API is an independent data service operated by Stunning Couches LLC. It is not affiliated with, endorsed by or operated by Underdog Fantasy.

Use it

Claude Code:

claude mcp add underdog -e UNDERDOG_API_KEY=ud_... -- npx -y underdog-api-mcp

Claude Desktop, Cursor, Windsurf and other JSON-configured clients:

{
  "mcpServers": {
    "underdog": {
      "command": "npx",
      "args": ["-y", "underdog-api-mcp"],
      "env": { "UNDERDOG_API_KEY": "ud_..." }
    }
  }
}

No key yet? demo_board, demo_changes and credit_costs work without one, so an agent can learn the response shape first. A free key (100 credits a month, no card) is at https://underdogapi.com/sign-up.

Related MCP server: propzapi

Tools

A tool the plan does not include answers with the API's 402 body: what is missing, the upgrade link and a few labelled sample rows. No credits are charged for it. Ask your user before upgrading.

Example prompts

• "Which NBA lines are discounted on the Higher side right now?"

• "How has this player's points line moved today?"

• "Rebuild the NHL board as of 7 pm Eastern yesterday and list shots lines."

Test

npm test                     # offline, against a local fake API
UNDERDOG_LIVE=1 npm test     # also calls the real keyless demo

Registry

server.json describes this package and the hosted remote for the official MCP registry (name com.underdogapi/underdog, verified through the underdogapi.com domain).