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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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Quickstart

Your first call to the nonprofit data API in under a minute.

1. Try it without a key

Every endpoint works keyless with generous rate limits. Look up an organization by EIN:

curl https://astra.northstartoolkit.com/v1/organizations/86-0481941

EINs are accepted with or without the hyphen. The response includes identity, the latest financial summary, people, and an index of every available filing, each record stamped with its tax year and source.

2. Get a free key

A free key lifts the rate limits. Create an account, open the Developer page in your workspace, and create a key. Then pass it as a bearer token:

curl https://astra.northstartoolkit.com/v1/organizations/86-0481941 \
  -H "Authorization: Bearer YOUR_API_KEY"

3. Pull a full filing

The flagship endpoint: the complete modeled 990 as JSON, with the header, revenue and expense line items, balance sheet, program accomplishments, and the compensation table.

curl https://astra.northstartoolkit.com/v1/organizations/86-0481941/filings/2023

4. Search with financial filters

Query primitives nobody else self-serves. Filter every US nonprofit by state, category, and financials:

curl "https://astra.northstartoolkit.com/v1/organizations?state=TX&ntee_prefix=K&revenue_min=5000000"

Or search semantically over missions and program text:

curl "https://astra.northstartoolkit.com/v1/search?q=youth+homelessness+housing+first"

Next steps

  • Full API reference (every endpoint, parameter, and response schema)
  • Use it from Claude (the MCP server wraps the same API for agents)
  • Limits and the Builder tier (commercial use starts at $49/month)

A note on freshness: the IRS publishes e-filed returns on its own schedule, often a year or more after the fiscal year ends. Every record carries its tax year, form type, and ingest date so staleness is always self-describing. We don't promise freshness the data can't have.