Illinois

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This guide contains public integration notes for Illinois. Use it for identifier formats, search behavior, and state-specific caveats. The live source of truth for coverage, pricing, data sources, documents, legal forms, roles, and status values is the pricing page.

Illinois coverage, pricing, and sources

Open the current catalog for supported datapoints, documents, sources, identifiers, and availability.

This jurisdiction may be in preview or limited availability. Check the live pricing page or contact support before relying on it in production.

State details below are preserved as integration notes. If a table or example conflicts with the live pricing page, use the pricing page as the source of truth and contact support.

Data Sources
Company Identifiers
Search Capabilities
Quirks & Gotchas
Mappings
- Legal Forms
- Entity Statuses
Data Availability

API access: US-IL is not yet part of the public countryCode enum. Contact us to enable it on your workspace. Requests sent with countryCode: "US-IL" will otherwise return 400 until the enum is expanded.

Data Sources

Illinois uses a single integration against the Illinois Secretary of State, Department of Business Services. The register covers approximately 2.8 million entities filed under the Illinois Business Corporation Act, the General Not-for-Profit Corporation Act, the Limited Liability Company Act, and related statutes, including domestic and foreign corporations, LLCs, professional service entities, benefit corporations, agricultural cooperatives, and not-for-profit corporations. The Illinois Business Data Transparency Act (Public Act 102-0049, effective 2022-01-01) requires the Secretary of State to publish daily bulk distributions of the business entity database. These bulk files are the sanctioned machine-readable path; Topograph uses them as the primary data source.

ILSOS daily bulk snapshot (fast, onboarding). Published daily at ilsos.gov. Covers corporation and LLC master records, annual report data, assumed names, and manager/member rosters. The snapshot refreshes daily; individual records may lag up to 24 hours from a filing event.
ILSOS public inquiry portal (authoritative, verification). The live public inquiry portal at apps.ilsos.gov is queried in real time for verification requests to refresh the basic profile (current legal name, entity status, registered agent, and effective date) directly from the source register. Officer rosters in verification responses continue to be served from the daily bulk snapshot.

Mode-based routing. Onboarding requests (mode: "onboarding") are served from the daily bulk snapshot. Verification requests (mode: "verification") query the live portal for the basic profile and supplement it with bulk-sourced officer data.

Company Identifiers

Query Identifiers

Identifier Type	Format	Example	Notes
ILSOS File Number	8 digits, zero-padded	`08142220`	Assigned by the Illinois Secretary of State. Illinois runs independent File Number sequences for corporations and LLCs. The same 8-digit number can refer to two different entities (one corporation, one LLC). To target a specific entity, supply the Topograph compound ID.
Topograph compound ID	`C` or `L` prefix + 8 digits	`C08142220`	Prefix `C` for corporations, `L` for limited liability companies. Use this form whenever you need to target a specific entity and avoid ambiguity.

Search by bare 8-digit File Number returns all matching entities across both the corporation and LLC sequences. Use the compound ID (C08142220 or L08142220) to resolve to a single entity. The identifiers.entityType field in the response confirms which family was matched.

Identifiers in API Response

Identifier	Format	Example	Found In
`fileNumber`	8 digits, zero-padded	`08142220`	All entities

Search Capabilities

Search Type	Pattern	Example	Match Type	Expected Results
By Name	2-100 chars	`"Walgreen"`	Starts-with (case-insensitive)	Multiple results
By File Number (bare)	8 digits	`08142220`	Exact	Up to 2 results (one corp + one LLC if both exist)
By Compound ID	`C` or `L` + 8 digits	`C08142220`	Exact	Single entity

Starts-with search. Name search anchors on the beginning of the legal name (case-insensitive). Use fuller query strings to narrow the result set, which is capped at 100 matches.

Quirks & Gotchas

Quirk	Details
File Number sequences overlap across entity families	Illinois maintains independent File Number sequences for corporations and LLCs. Two different entities can share the same 8-digit number. Always use the Topograph compound ID (`C` or `L` prefix) when you need to unambiguously identify a single entity.
LLC status may default to active	The bulk distribution for LLCs does not reliably expose the dissolution status field in v1. Dissolved LLCs may appear as active. The live portal provides the current status in verification mode. Use `mode: "verification"` when LLC status accuracy is required for compliance.
Annual report freshness	Corporations and LLCs file one annual report per year. Officer and address data in the snapshot may be up to 12 months old, reflecting the most recent annual filing. This is a structural property of the Illinois filing cadence, not a Topograph limitation.
LLCs disclose managers and members	Unlike many US states, Illinois LLCs disclose their managers and (where applicable) members in the public bulk distribution. `legalRepresentatives` is populated for LLCs. Do not assume an empty array for LLC entities.
Limited Partnerships and LLPs are out of scope for v1	LPs and LLPs are available through the live portal but are not included in the daily bulk distribution. They are excluded from v1 coverage.
No ownership percentages	Illinois does not collect or publish ownership percentages for any entity type. `legalRepresentatives` includes names and roles but no equity stakes.
No activity codes	The Secretary of State does not collect NAICS, NACE, or ISIC codes. A coarse 56-entry purpose code is available for corporations only and is not currently surfaced.
Series LLCs	Illinois is one of the few states that allows Series LLCs. Each individual series within a parent LLC receives its own File Number and status. Individual series are surfaced in the API as distinct entities, linked to the parent via the company record.
State-level DBAs	Assumed names (DBAs) registered at the state level are included in the bulk distribution and indexed for search. County-level DBA registrations are not included.
Nonprofits are in scope	Not-for-profit corporations filed under the Illinois General Not-for-Profit Corporation Act are included in the corporation bulk distribution and covered by this integration. Fundraising registration through the Illinois Charitable Trust Bureau is out of scope.

Mappings

Legal Forms

Legal form is derived from the entity type code in the ILSOS bulk distribution, sourced from the published Corp and LLC data dictionaries. The full legal form table is available on the pricing page.

Illinois entity types (summary)

Local Name	Standardized	Category
Domestic Corporation	Corporation	Business Corporation Act
Foreign Corporation	Corporation	Business Corporation Act
Domestic Benefit Corporation	Corporation	Business Corporation Act
Foreign Benefit Corporation	Corporation	Business Corporation Act
Domestic Professional Service Corporation	Corporation	Business Corporation Act
Foreign Professional Service Corporation	Corporation	Business Corporation Act
Domestic Medical Corporation	Corporation	Business Corporation Act
Domestic Close Corporation	Corporation	Business Corporation Act
Domestic Not-For-Profit Corporation	NonprofitOrganization	Not-for-Profit Corporation Act
Foreign Not-For-Profit Corporation	NonprofitOrganization	Not-for-Profit Corporation Act
Religious Corporation	NonprofitOrganization	Not-for-Profit Corporation Act
Agricultural Cooperative	Cooperative	Ag-cooperative (unique to IL)
Domestic Limited Liability Company	LimitedLiabilityCompany	LLC Act
Foreign Limited Liability Company	LimitedLiabilityCompany	LLC Act
Domestic Professional Service LLC	LimitedLiabilityCompany	LLC Act
Foreign Professional Service LLC	LimitedLiabilityCompany	LLC Act
Low-Profit Limited Liability Company (L3C)	LimitedLiabilityCompany	LLC Act
Series Limited Liability Company	LimitedLiabilityCompany	LLC Act (unique to IL)
Series LLC, Individual Series	LimitedLiabilityCompany	LLC Act (unique to IL)

The full legal form table with source codes and ISO 20275 mappings (where available) is on the Illinois pricing page.

Entity Statuses

Status values are sourced from the ILSOS bulk data dictionaries (Corp CORP-STATUS field and LLC LL-STATUS field) and from the live portal in verification mode. “Not Good Standing” is a derived status emitted when the current annual report has been invoiced but not yet paid.

Status	Applies To
Goodstanding	Corps and LLCs
Not Good Standing	Corps (derived)
Involuntary Dissolution	Corps
Voluntary Dissolution	Corps and LLCs
Withdrawn	Foreign entities
Merged	Corps
Bankruptcy Filed	Corps
Revoked	Corps
Administratively Dissolved	Corps and LLCs
Dissolved	Corps and LLCs
Converted	Corps
Cancelled	LLCs

LLC status in onboarding mode. The bulk LLC master record does not reliably expose the dissolution status field in v1. All LLCs not explicitly marked inactive default to Goodstanding in onboarding mode. Use mode: "verification" to get a live status read from the portal when LLC status accuracy is required.

Data Availability

Data Point	Available	Notes
Company name	Yes	Current legal name
Company status	Partial	Reliable for corporations in both modes. LLCs: live status in verification mode; onboarding mode defaults to active.
Registration date	Yes	ILSOS initial filing date
Legal address	Yes	Street address, city, state, ZIP from the annual report
Legal form	Yes	Closed enum mapped to standardized categories
Legal representatives	Yes	Corps: president and secretary. LLCs: managers and members. LP/LLP: out of scope for v1.
Registered agent	Partial	Available in verification mode from the live portal. Not reliably in the bulk snapshot.
Assumed names (DBAs)	Yes	State-level assumed names from the bulk distribution
Series LLC sub-series	Yes	Each series returned as a distinct entity with its own File Number
Activity codes	No	Not collected by the Illinois Secretary of State
Shareholders	No	Not filed with the Secretary of State for any entity type
UBOs	No	No public beneficial ownership register at the state level
Trade Register Extract	Yes	Free printed PDF of the ILSOS public inquiry detail page, included at no extra charge with every data request
Certificates of Good Standing	Roadmap	Paid document issued by the Secretary of State. Not currently offered through Topograph.
Certified copies	No	Paid documents mailed by the Secretary of State; not available through the public portal
Financial data	No	Not collected
County-level DBAs	No	County-level DBA filings are not part of the Secretary of State database

Example API Responses

Search by Name

curl -X POST "https://api.topograph.co/v2/search?country=US-IL&query=Acme" \
  -H "x-api-key: YOUR_API_KEY"

[
  {
    "id": "C09000001",
    "legalName": "ACME MANUFACTURING, INC.",
    "countryCode": "US-IL",
    "matchReason": {
      "matchType": "default"
    },
    "address": {
      "region": "IL",
      "countryCode": "US"
    }
  }
]

Search by Compound ID

curl -X POST "https://api.topograph.co/v2/search?country=US-IL&query=C09000001" \
  -H "x-api-key: YOUR_API_KEY"

[
  {
    "id": "C09000001",
    "legalName": "ACME MANUFACTURING, INC.",
    "countryCode": "US-IL",
    "matchReason": {
      "matchType": "id"
    }
  }
]

Company Profile

curl -X POST "https://api.topograph.co/v2/company" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"countryCode": "US-IL", "id": "C09000001", "dataPoints": ["company", "legalRepresentatives"], "mode": "onboarding"}'

{
  "company": {
    "id": "C09000001",
    "countryCode": "US-IL",
    "identifiers": { "fileNumber": "09000001" },
    "legalName": "ACME MANUFACTURING, INC.",
    "registrationDate": "2005-03-15",
    "legalForm": {
      "localName": "Domestic Corporation",
      "standardized": "Corporation"
    },
    "legalAddress": {
      "street": "123 Commerce Drive",
      "city": "Springfield",
      "region": "IL",
      "postalCode": "62701",
      "countryCode": "US"
    },
    "status": {
      "active": true,
      "label": "Goodstanding"
    }
  },
  "legalRepresentatives": [
    {
      "role": "President",
      "individual": {
        "name": { "fullName": "Jane A. Smith" }
      }
    },
    {
      "role": "Secretary",
      "individual": {
        "name": { "fullName": "Robert B. Johnson" }
      }
    }
  ]
}

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Illinois coverage, pricing, and sources

Table of Contents

Data Sources

Company Identifiers

Query Identifiers

Identifiers in API Response

Search Capabilities

Quirks & Gotchas

Mappings

Legal Forms

Entity Statuses

Data Availability

Example API Responses

Search by Name

Search by Compound ID

Company Profile

​Start here

Illinois coverage, pricing, and sources

​Table of Contents

​Data Sources

​Company Identifiers

​Query Identifiers

​Identifiers in API Response

​Search Capabilities

​Quirks & Gotchas

​Mappings

​Legal Forms

​Entity Statuses

​Data Availability

​Example API Responses

​Search by Name

​Search by Compound ID

​Company Profile

Start here

Table of Contents

Data Sources

Company Identifiers

Query Identifiers

Identifiers in API Response

Search Capabilities

Quirks & Gotchas

Mappings

Legal Forms

Entity Statuses

Data Availability

Example API Responses

Search by Name

Search by Compound ID

Company Profile