Nonprofit data
without the enterprise gate.

The legacy options force a bad tradeoff: expensive enterprise platforms with sales gates, or raw IRS files that take real engineering work to normalize. 501see gives developers the missing middle: documented API access, stable JSON, and a free path to start with nonprofit verification.

Verify a nonprofit for free.

GET https://api.501see.app/api/v1/orgs/{ein}
Enter an EIN to see the response.

Built for the gap in the market.

Candid and CauseIQ are built for large research budgets. IRS data is built for compliance, not application developers. 501see is built for teams that need to ship: public docs, self-serve keys, normalized fields, and pricing that does not require an enterprise buying process.

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Skip the sales gate. Sign up, get a key, and start testing.

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Skip the IRS plumbing. Work with normalized JSON and semantic field names.

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Move from verification to filings, grants, officers, foundations, and exports.

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Use one OpenAPI spec for docs, Postman, SDK generation, and LLM tools.

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Connect through MCP when your workflow is agent-first instead of REST-first.

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Pay monthly instead of committing to a large annual data contract.

Verify nonprofit status for free. Upgrade for full access.

A simple lookup shouldn't require a four-figure subscription.

Free

$0

Verify nonprofit organizations by EIN.

  • EIN lookup
  • Basic nonprofit data
  • Optional name search
  • Self-serve signup

Pro

$99/month

For teams building nonprofit products, automations, and data pipelines without waiting on enterprise sales.

  • Filings, grants, officers, and foundations
  • Recommended funders and similar orgs
  • Exports
  • MCP access
  • 30 req/s rate limit

Cancel anytime. No sales call.

Test the data before you commit.

Inspect a real lookup response, import the OpenAPI spec, and move to API-key access when you are ready to integrate.

Sign Up

Frequently Asked Questions

How is 501see different from Candid or CauseIQ?

Those platforms are strong enterprise research products, but API access usually means sales conversations, licensing review, and annual contracts. 501see is built for developers who want to evaluate and integrate nonprofit data directly.

Is there a free tier?

Yes. Developer Free is built for nonprofit verification by EIN lookup, with optional name search if you need to find an EIN first.

What does Pro include?

Pro adds filings, grants, officers, foundation discovery, funder portfolios, recommended funders, exports, higher limits, and MCP.

Why not use raw IRS files directly?

Raw IRS data is public, but it is not product-ready. 501see handles XML parsing, form differences, schema changes, and field mapping so you can build against stable JSON.

How fresh is the data?

501see updates IRS filing data monthly.

Do I need an annual contract?

No. 501see is designed for self-serve evaluation and monthly API access.