Illinois SOS Business Search - LLCs, Corporations & Registered Agents

Look up any Illinois LLC or corporation by company name or file number, or list the LLCs and corporations newly organized in Illinois between two dates. Every row comes from the official Illinois Secretary of State business register, refreshed daily: status, entity type, dates, registered agent, managers and officers.

No API key, no login, no proxy settings. Results in seconds.

What you get

Field	Example
fileNumber	12345678 - the Illinois file number (unique within LLCs or within corporations)
entityFamily	LLC or Corporation
name	ACME HOLDINGS LLC
entityType	Limited Liability Company - IL, Domestic business corporation, Not-for-profit corporation, Foreign business corporation
status, statusDate	Good standing, Administratively dissolved, Revoked... and the date it took effect
formedIn	Home state of a foreign LLC (DE, WY...), IL for domestic entities
organizationDate	Date organized or qualified in Illinois
principalAddress	LLC records office address (corporations: not held in the register)
registeredAgent, agentType, agentAddress, agentCounty, agentSince	Registered agent and the Illinois county of the agent's address
managementType, managers	LLC managers / members with role and address; corporation president and secretary
businessCode, homeStateCode, dissolutionDate	As held by the state
snapshotDate	The date of the register the row was read from
query, matchType	Which of your queries found it, and how (file number, exact name, all words, new filing)

How to use it

Search by name or file number

{
  "searchQueries": ["Abbott Laboratories", "Acme Holdings LLC", "12345678"],
  "maxResultsPerQuery": 50
}

• A name finds every entity whose name contains all its words. Endings such as LLC, Inc, Corp, Company and Ltd are ignored for matching - but an entity whose full name matches exactly is listed first, then names that start with your first word, then the rest.
• A query made of digits (up to 8) is a file number. It returns the LLC and the corporation with that number, if both exist.
• maxResultsPerQuery (default 50) stops a broad word from returning thousands of rows. Set 0 for up to 1,000.
• entityFamilies limits to llc or corporation; onlyActive keeps only entities in good standing or reinstated.

New filings by date

{
  "mode": "newFilings",
  "dateFrom": "2026-10-01",
  "dateTo": "2026-10-16",
  "entityFamilies": ["llc"]
}

Lists every entity organized or qualified in Illinois inside the window (the last 13 months are available). Illinois registers roughly 500-600 new entities per business day.

Daily feed: schedule the actor once a day with a 7-day window and onlyNewSinceLastRun: true. Each run then delivers only the entities it has not delivered before - including filings the state enters a day or two late - and nothing twice. The memory is a key-value store in your own account (stateStoreName).

Use cases

• KYB and onboarding: confirm a counterparty exists, is in good standing and who its registered agent is.
• Lead generation: new Illinois LLCs and corporations every day, with the agent's county for territory routing.
• Compliance monitoring: re-check a list of file numbers on a schedule and watch for status changes (dissolved, revoked, agent vacated).
• Due diligence and research: find every entity whose name contains a brand or family name.

Pricing

Pay per result: you are charged per entity record delivered. Queries that find nothing cost nothing.

FAQ

How fresh is the data? The register is refreshed daily; snapshotDate on each row tells you the date it reflects. Filings made today appear after the state processes them, usually the next day.

Why does an entity appear twice for one file number? Illinois numbers LLCs and corporations separately, so one number can belong to one of each. entityFamily tells them apart.

Do corporations have an address? The Illinois register does not hold a business address for corporations - only the registered agent's address and the officers. LLCs have a records-office address.

Personal data. Registered agents, managers and officers are often private individuals. The data is public record; you are responsible for using it lawfully (for example under the CAN-SPAM Act, TCPA and state privacy laws when you use it for marketing).

Can I search by agent or by address? Not yet - tell us in the Issues tab if you need it.