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grantleydev

Posted on • Originally published at filed.dev

I Built a Free API for U.S. Business Entity Lookups

#api #webdev #opensource #startup

Every developer hits this wall eventually: you need to look up whether a business is registered, who the officers are, or when it was formed. And every state has its own janky website with different formats, CAPTCHAs, and broken search.

I got tired of scraping Secretary of State websites, so I built Filed — a free API that normalizes business entity data across U.S. states into one clean endpoint.

The Problem

Say you're building:

  • A KYC/AML compliance check
  • A CRM that enriches company profiles
  • A legal tech tool that verifies entity status
  • A due diligence workflow

You need entity data. Your options:

  1. Scrape each state yourself — 50 different sites, different formats, constant maintenance
  2. Pay $500+/month for enterprise data providers (OpenCorporates, Dun & Bradstreet)
  3. Use Filed — free tier, 100 lookups/month, clean JSON

How It Works

One endpoint. State code + search term. That's it.

curl "https://filed.dev/api/v1/search?state=FL&q=Apple" \
  -H "Authorization: Bearer YOUR_KEY"
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Response:

{
  "results": [
    {
      "name": "APPLE INC.",
      "entityNumber": "F05000002957",
      "status": "Active",
      "type": "Foreign Profit Corporation",
      "filingDate": "2005-06-28",
      "state": "FL"
    }
  ],
  "count": 25,
  "source": "Florida Department of State"
}
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Entity details with officers, registered agent, and filing history:

curl "https://filed.dev/api/v1/entity/FL:F05000002957" \
  -H "Authorization: Bearer YOUR_KEY"
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Currently Supported States

State Source Data Quality
Florida Sunbiz.org Excellent
New York DOS Good
Oregon SOS Good
Pennsylvania DOS Good
Colorado SOS Good
Alaska Commerce Good
Connecticut SOTS Good
Iowa SOS Good
Washington DC DCRA Good

9 states and counting. The architecture makes it straightforward to add new sources.

Federal Data Enrichment

Beyond state filings, you can enrich any entity with federal data:

curl "https://filed.dev/api/v1/entity/FL:F05000002957?include=federal" \
  -H "Authorization: Bearer YOUR_KEY"
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This pulls from SEC EDGAR, USASpending (federal contracts), Senate lobbying disclosures, SAM.gov, and IRS nonprofit data — all merged into one response.

Free Tier

  • 100 API calls/month
  • All states included
  • No credit card required
  • Get your key at filed.dev/developers

For higher volume: Developer ($49/mo, 5K calls), Business ($199/mo, 25K calls + federal data), Scale ($499/mo, 100K calls). Also available on RapidAPI.

Tech Stack

For the curious:

  • Next.js API routes on Vercel
  • Supabase for cached entity data
  • Socrata Open Data API for states that publish to open data portals (NY, OR, CT, IA)
  • Custom adapters for states without open data (FL, PA, CO, AK, DC)
  • Federal APIs — SEC EDGAR, USASpending, Senate LDA, SAM.gov, IRS/ProPublica
  • Rate limiting and API key auth on all routes

Use Cases

The most common use cases so far:

  1. Legal tech — Verifying entity status before filing documents
  2. Fintech — KYC checks during onboarding
  3. Real estate — Identifying LLC ownership of properties
  4. Sales teams — Enriching CRM data with entity details
  5. Researchers — Bulk analysis of business formations by state

What's Next

  • More states (targeting all 50 by end of year)
  • Bulk search endpoints
  • Webhook notifications for entity status changes
  • Officer/agent cross-referencing across states

Try It

  1. Go to filed.dev/developers
  2. Get a free API key
  3. Make your first search

If you're building something that needs business entity data, stop scraping state websites. Life's too short.

Questions? Feature requests? Drop a comment below.

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