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Northstar Toolkit is the nonprofit data platform — every US nonprofit and foundation from IRS 990 filings, as free search, a developer API, and an MCP server for AI agents. The 990 base layer is free, and stays free.
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    Documentation

    Quickstarts, guides, and the full API reference for the nonprofit data API.

    Quickstart

    Your first API call in under a minute — keyless, then with a free key.

    API Reference

    Every endpoint, parameter, and response schema — generated from the API itself.

    MCP / Agents

    Point Claude or any MCP client at the warehouse. One URL, no key needed.