Free US company registry APIs: state-by-state guide

Every endpoint on this page was live-probed on 2026-07-28 by the Aidenix Atlas catalog.

What is a US company registry API?

A US company registry API is a public endpoint that returns official incorporation records — legal name, entity ID, registration date, status, and registered agent — straight from a state Secretary of State database. There is no single federal registry: each of the 50 states maintains its own. In our data — the Aidenix Atlas catalog, where every endpoint is live-probed — 4 states expose theirs through free Socrata-based APIs with no API key, together holding 10,137,727 entity records. What you get from an open registry endpoint:

• Official records published by the state itself, not scraped or resold copies.
• Coverage back decades — New York alone serves 4,228,686 corporation records dating to 1800, according to the New York Department of State dataset.
• JSON over plain HTTP, so any language or no-code tool can consume it.

Key facts at a glance

A key-facts table is the 60-second version of this page: 4 open states, 10,192,987 records, $0 — every row from our own probe run of 2026-07-29, according to the Aidenix Atlas catalog logs:

Which states offer free business registry APIs?

An open state registry is a portal whose Secretary of State publishes the full entity file with an API, not just a search form. In our data, 4 states qualify today; the remaining 46 offer only web search forms or paid bulk files. Status below is what each endpoint actually answered in our probe run of 2026-07-28:

Every count in that table is a live count(*) we ran against each register on 2026-07-29, not a figure copied from a catalog page — and all three came back higher than the numbers we published a day earlier, which is the argument against caching a state register and calling it current. California is absent from this table on purpose: its register has no open API, and we published the probe that shows why.

Why one row says «unreachable», and why we left it in. On 2026-07-28 the Oregon portal's host did not resolve at all — not a 500, not a timeout on a slow query, but no DNS route. The same outage hit on 2026-07-24 and the portal returned within the hour, so this reads as infrastructure flapping rather than a retired dataset. We publish the failure instead of quietly dropping the row, because a coverage table that only shows successes is a marketing asset, not a working document: the practical lesson for anyone building on state registries is that portal uptime is the weakest link in the stack, and your pipeline needs a retry path.

All 4 run on the Socrata Open Data API, so the query syntax is identical across states — only the domain and dataset ID change. Each dataset link opens its access card with the exact endpoint, auth, and a copy-paste query.

How do you query a state registry API?

A registry query is a single HTTP GET with SoQL parameters — Socrata's SQL-like filter syntax — and no authentication. We tested each endpoint on 2026-07-28; the steps that worked:

• Pick the state portal and dataset ID, for example data.ny.gov and n9v6-gdp6 for New York corporations.
• Filter with SoQL: $where=entity_name like '%25ACME%25' matches by company name.
• Page with $limit and $offset; a single request returns up to 50,000 rows.
• Add a free Socrata app token if you poll often — according to Socrata documentation, requests without a token share a throttled pool, while a token grants your app its own rate limit.

# %25 is a URL-encoded % — the SoQL wildcard; forgetting it returns exact matches only
curl "https://data.ny.gov/resource/n9v6-gdp6.json?\$where=entity_name%20like%20'%25ACME%25'&\$limit=10"

Which state to query follows from what you know about the company:

• If you have a company name → New York, Oregon or Connecticut; Colorado indexes by address and entity ID, not name.
• If you have an address and need everyone at it → Colorado or Connecticut; this is how shell clusters surface.
• If you need a company outside these 4 states → no free API exists; fall back to SEC EDGAR if the company files, or the state's web form.

What data fields do registries return?

Registry records share a core structure of 5 field groups across all 10,137,727 records in the open states above, returned under state-specific names according to each portal's published data dictionary. The fields and what each is worth in practice:

• Legal entity name, exactly as registered with the Secretary of State.
• State entity ID — the join key for linking filings, permits, and UCC liens.
• Initial filing date, which doubles as a company-age signal for lead scoring.
• Registered agent name and address, often the only public contact for a private company.
• Entity status (active, dissolved, delinquent) and jurisdiction of formation.

In our data, registered-agent address is the highest-leverage field of the 5: it resolves shell-company clusters, since thousands of entities can share one agent address, and that concentration is itself a risk signal.

Can you get all 50 states from one free API?

No. A unified free federal registry API does not exist — that is the honest limitation of the open-data route, and any vendor claiming otherwise is reselling state data. The workable free stack, in our data, is a 3-layer join:

• SEC EDGAR: federal and free, but only covers SEC filers — roughly 800,000 entities versus an estimated 30+ million registered US businesses.
• The 4 open Socrata states above: 10,137,727 official records with identical query syntax.
• California bizfileonline: the largest state economy, searchable by company name without a key.

That combination answers the majority of US company-lookup queries we tested, at zero data-license cost, with commercial aggregators needed only for the long tail of closed states.

Frequently asked questions

Why do only 4 states have a real API? Because publishing an API is a state open-data policy choice, not a legal requirement. Most Secretaries of State satisfy public-record obligations with a web search form; some sell bulk files. The 4 above happen to run Socrata, which exposes every dataset as an API by default.

Is there a free API for California, Texas or Delaware? Not in the Socrata sense. California's bizfileonline is searchable programmatically by name but has no documented public API; Delaware and Texas offer paid or form-only access. In our catalog, California is tracked separately from these 4 for exactly that reason.

Can I use this data commercially? Generally yes — these are public records — but terms are set per portal, not federally. Read the specific dataset's terms before redistributing bulk copies; querying and enriching your own records is uncontroversial across all 4.

How we verify these claims

Our verification method is a live probe, not a citation chain — every status and count on this page comes from requests we sent ourselves on 2026-07-28. What the probe run covers, in our data:

• Endpoint liveness: 3 of the 4 state endpoints answered HTTP 200; Oregon's host did not resolve, and the table above says so.
• Record counts: taken from each portal's own dataset metadata, not from vendor marketing.
• Query syntax: every SoQL example on this page was executed, not composed from documentation.
• Freshness contract: when a source drifts or dies, the probe fleet flags it and this page gets re-verified — the «last probed» date above is that promise, including when the news is bad.

Source facts from the Aidenix Atlas catalog, probed 2026-07-28. Found an error? The catalog re-probes on every report.