Self-serve nonprofit data API
Get broad nonprofit and IRS 990 data without an enterprise sales process. Start free with organization lookup and verification, then add full read access, exports, and webhooks as your workflow grows.
Find, then verify, a nonprofit for free.
Use the live demo to search by organization name and get up to five likely matches. Then use the EIN to verify the organization with a real API lookup.
Use the same normalized nonprofit data in your application, analysis, or internal workflow. Create a free account for an API key, then copy a request from the docs.
Verify a nonprofit
curl "https://api.501see.app/api/v1/orgs/13-1837418" \ -H "Authorization: Bearer YOUR_API_KEY"
Fetch normalized filing fields
curl "https://api.501see.app/api/v1/orgs/13-1837418/filings/latest?preset=financials" \ -H "Authorization: Bearer YOUR_API_KEY"
Search grant activity
curl "https://api.501see.app/api/v1/grants?recipient_name=food%20bank&state=GA&limit=5" \ -H "Authorization: Bearer YOUR_API_KEY"
Search, understand, export, and integrate public nonprofit data across organizations, filings, grants, officers, and foundations. The IRS is the source. 501see handles the normalization, field mapping, and API contract so you can use the data without starting with raw files or an enterprise contract.
Resolve an organization name, confirm its EIN, and check its latest filing.
Explore normalized organization, filing, grant, officer, and foundation data.
Create filtered exports for a spreadsheet, warehouse, CRM, directory, or internal analysis.
Subscribe to supported data changes with signed webhooks instead of polling for them.
Start with docs and OpenAPI, then use API keys or MCP when your workflow needs them.
Choose the level of access that fits the work in front of you.
Free
Find organizations by name, verify them by EIN, and check the latest filing.
Basic
Full read API access for deeper analysis, enrichment, and ongoing access to public nonprofit data.
Pro
For teams moving a filtered dataset into their own workflow and keeping selected records current.
Cancel anytime. No sales call.
Create a free account to use name search, EIN lookup, and latest filing lookup in your own workflow. Browse the API contract when you are ready to go deeper.
Those platforms offer broader enterprise research and enrichment products. 501see is for people who need usable, 990-derived nonprofit data in their own work, without starting with a sales process or raw IRS files.
Developers, researchers, nonprofit power users, and data teams can all start with a nonprofit lookup, then use structured records, exports, or integrations as their work grows.
Yes. Developer Free includes bounded organization name search, EIN lookup, and latest-filing lookup for verification workflows.
Basic adds the full read API surface, including filings, grants, officers, foundation discovery, funder portfolios, and MCP. Pro adds exports and webhooks.
Raw IRS data is public, but it takes work to use well. 501see handles XML parsing, form differences, schema changes, and field mapping so you can work with consistent records instead.
501see updates IRS filing data monthly.
No. 501see is designed for self-serve evaluation and monthly API access.