Business Entity Verification API: Complete Developer Guide

What is a Business Entity Verification API?

A business entity verification API automates the process of checking business registration status, ownership details, and legal compliance information from state Secretary of State databases. Instead of manually visiting state websites or filing records requests, developers can programmatically query official business entity data in seconds.

The OpenSOSData REST API is built specifically for this use case. It connects directly to 11 US Secretary of State databases—Delaware, Arkansas, Texas, Colorado, Georgia, Minnesota, North Dakota, Idaho, Alabama, North Carolina, and Florida—returning verified entity information instantly.

Why Business Entity Verification Matters

Whether you're building a lending platform, compliance dashboard, or B2B marketplace, verifying counterparties against official state records is critical. Manual verification is slow and error-prone. A business entity verification API eliminates human error and scales verification workflows from dozens to thousands of entities per day.

Common use cases include:

Know-Your-Customer (KYC) and onboarding workflows
Counterparty risk assessment
Fraud detection and prevention
Supply chain verification
Regulatory compliance reporting
Due diligence automation

OpenSOSData vs. Competitors

The market for business entity verification APIs includes several players. Here's how OpenSOSData compares on pricing alone:

Competitor Pricing (per lookup):

OpenCorporates: $0.10–$0.50
Cobalt Intelligence: $0.50–$2.00
Middesk: $1.00+
OpenSOSData: $0.0314 (Pi pricing)

OpenSOSData's Pi pricing ($0.0314 per lookup) is fundamentally lower. At this rate, $3.14 (one Pi dollar) covers 100 lookups. There are no subscriptions, minimum commitments, or hidden fees. You pay only for what you use.

What Data Does the API Return?

Each lookup returns comprehensive entity data from official state records:

Entity name (legal registered name)
Entity type (LLC, Corporation, Partnership, etc.)
Entity ID (state-assigned identifier)
Current status (Active, Dissolved, Inactive, etc.)
Formation date (original incorporation or registration date)
Registered agent name and address
Principal business address
Officers and management details

This data is queried directly from Secretary of State databases, not aggregated from third-party sources, ensuring accuracy and legal compliance.

Caching and Performance Optimization

OpenSOSData includes a 7-day Redis cache for frequently verified entities. If you look up the same business entity within 7 days, the cached result is returned instantly—at no cost. This dramatically reduces API costs for workflows that verify overlapping entity lists.

For mission-critical workflows requiring real-time data, use the ?fresh=true parameter to force a live scrape of the current state database. This ensures you always have the latest status, even if it differs from cached data.

Quick Start

Step 1: Sign Up and Fund Your Wallet

Visit https://opensosdata.com to join the waitlist. Once approved, add funds to your account (minimum $3.14 for 100 lookups). No credit card required—pay per lookup as you go.

Step 2: Review the OpenAPI Documentation

The complete API specification is available at https://opensosdata.com/openapi.yaml. It includes request/response schemas, error codes, and state-specific field availability.

Step 3: Make Your First API Call

Here's a real curl example to verify a Delaware LLC:

curl -X POST https://api.opensosdata.com/v1/lookup \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "state": "DE",
    "entity_name": "Apple Inc",
    "entity_type": "CORP"
  }'

Example Response:

{
  "entity_name": "APPLE INC.",
  "entity_type": "CORP",
  "entity_id": "1018724",
  "status": "ACTIVE",
  "formation_date": "1977-04-01",
  "registered_agent": {
    "name": "CORPORATION SERVICE COMPANY",
    "address": "251 LITTLE FALLS DRIVE, WILMINGTON, DE 19808"
  },
  "principal_address": "ONE APPLE PARK WAY, CUPERTINO, CA 95014",
  "officers": [
    {
      "name": "TIMOTHY D COOK",
      "title": "CHIEF EXECUTIVE OFFICER"
    }
  ],
  "cached": false,
  "cost": 0.0314
}

Step 4: Integrate Into Your Workflow

Use the returned data to populate compliance dashboards, trigger alerts on status changes, or gate user onboarding based on entity verification. The API returns structured JSON, making integration straightforward in any language.

Pricing Model Explained

OpenSOSData uses Pi pricing—a whimsical but serious pricing strategy tied to the mathematical constant π (3.14159...). Each lookup costs exactly $0.0314, which is π cents.

Why? Because business entity verification is a fundamental operation. The pricing is irrational, infinite, and non-negotiable—just like π. And practically speaking, it's the lowest per-lookup cost in the industry.

No subscriptions, no overage fees, no per-month minimums. If you use the API 10 times in a month, you pay for 10 lookups. If you use it 10,000 times, you pay for 10,000 lookups. Cached hits are free.

Coverage and Roadmap

OpenSOSData currently covers 11 states with active database scraping: Delaware, Arkansas, Texas, Colorado, Georgia, Minnesota, North Dakota, Idaho, Alabama, North Carolina, and Florida. These states represent significant business formation centers and emerging hubs.

If your compliance workflow requires other states, check the docs or contact support—additional state coverage is continuously expanding based on demand.

Error Handling and Rate Limits

The API enforces rate limits to ensure fair usage and system stability. Typical limits are generous for production workloads. Error responses include clear status codes and messages:

200 OK: Entity found and returned
404 Not Found: Entity does not exist in state database
400 Bad Request: Missing or invalid parameters
401 Unauthorized: Invalid or missing API key
429 Too Many Requests: Rate limit exceeded
500 Server Error: Temporary service issue

All errors include structured JSON with actionable remediation guidance.

Use Cases in Practice

Lending and Fintech: Automated KYC on new business applicants by verifying entity status, officers, and registered agent details before underwriting.

Compliance and Legal: Bulk verify counterparties, suppliers, or portfolio companies against Secretary of State records to identify inactive entities or address mismatches.

Marketplace Platforms: Gate vendor or seller onboarding by requiring active business entity status in supported states.

Credit Risk: Monitor entity status changes month-over-month to flag dissolution, revocation, or name changes that signal financial distress.

Getting Started Now

The barrier to entry is minimal. You need only an API key and a few dollars in your account. There's no sales call, no contract negotiation, no per-month commitment. Sign up, authenticate, and start verifying entities in minutes.

Verify US Business Entities in Real-Time with OpenSOSData