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

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, 4 states currently expose theirs through free Socrata-based APIs with no API key required, and together they cover more than 10 million 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.

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 — the Aidenix Atlas catalog, with every endpoint live-probed on 2026-07-24 and returning HTTP 200 — 4 states qualify today, holding 10,137,727 records combined. The remaining 46 states offer only web search forms or paid bulk files.

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: 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 request with SoQL parameters — Socrata's SQL-like filter syntax — and no authentication. We tested each of the 4 endpoints on 2026-07-24; 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.

curl "https://data.ny.gov/resource/n9v6-gdp6.json?\$where=entity_name%20like%20'%25ACME%25'&\$limit=10"

The response is plain JSON — no SDK, no signup, no scraping required.

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 a single agent address, and that concentration itself is 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.

Test page. Source facts pulled from the Aidenix Atlas catalog of verified data sources; record counts as probed on 2026-07-24. Not yet editorially reviewed.