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Clerkfield API documentation

Everything you need to call Clerkfield from your own systems: authentication, each endpoint with its parameters and an example response, errors, and the OpenAPI spec.

Get an API key OpenAPI spec

Quickstart

  1. 01

    Create a free account

    Sign up at clerkfield.com/app. No sales call and no card.

  2. 02

    Create an API key

    Open your profile in the app and create a key. It's shown once, so store it in your secrets manager.

  3. 03

    Make your first call

    Check the key with GET /v1/account/me, then run a business check.

curl -H "Authorization: Bearer $CLERKFIELD_KEY" "https://clerkfield.com/v1/account/me"

curl -H "Authorization: Bearer $CLERKFIELD_KEY" \
  "https://clerkfield.com/v1/business-check?name=Pizza%20and%20Company&state=KY&owner=Jane%20Doe"

Reference

Base URL https://clerkfield.com. All endpoints use GET and return JSON. Responses are UTF-8; dates are YYYY-MM-DD.

Authentication

Every endpoint except coverage needs an API key. Requests without one get a 401 error.

Authorization: Bearer cf_live_…

Business check

GET /v1/business-check

Checks a business against its state's registry and returns a verdict with the reasons. How verdicts work.

ParameterRequiredDescription
nameYesThe business name, as the applicant gave it.
stateYesTwo-letter state code. Covered: AL, AR, CO, CT, FL, ID, KY, MN, ND, NJ, NM, NY, OR, PA, TX.
ownerNoThe applicant's name, to check against the officers the state lists.
min_monthsNoMinimum months in business. Defaults to 6.

Returns verdict (pass, review or fail), matchQuality (exact, strong, possible or none), match (the state's record: legal name, entity id, status and the state's own status wording, entity type, formation date, months in business, addresses, registered agent, officers, every other published field and the source with its date), alternatives (similar names), flags (code, severity and message) and checkedAt.

Lien search

GET /v1/liens

Lists UCC filings against a business, or filed by a lender. About lien search.

ParameterRequiredDescription
stateYesTwo-letter state code. Covered: AL, AR, CT, FL, ID, KY, NE, NJ, NM, RI.
debtorOne of the twoThe business name.
secured_partyOne of the twoThe lender name. Works in CT, FL, NE, NM, RI.
include_inactiveNoSet to false to return active filings only. Defaults to true.
 
{
  "summary": {
    "total": 3, "active": 2, "lapsed": 1, "terminated": 0,
    "activeSecuredParties": ["Northstar Capital LLC", "Bluegate Funding Inc"],
    "notPublished": []
  },
  "filings": [{
    "fileNumber": "2026-4471029",
    "filedOn": "2026-09-18", "lapseOn": "2031-09-18",
    "status": "active",
    "debtors": [{ "name": "HARBOR STREET BAKERY LLC" }],
    "securedParties": [{ "name": "NORTHSTAR CAPITAL LLC" }],
    "collateral": "All assets of the debtor",
    "events": [],
    "source": { "name": "Connecticut Secretary of the State, UCC Lien Filings" }
  }]
}

Fields a state doesn't publish for free are listed in summary.notPublished and in each filing's unavailable, so an empty list means "not published", not "none".

Coverage

GET /v1/coverage

Every state and what each check covers there. Public: no key needed. Open it or see the coverage page.

Account

GET /v1/account/me

Returns the account a key belongs to. Use it to test a key when you connect Clerkfield to another tool. It costs nothing and isn't counted as usage.

{
  "org": { "id": "8c1f…", "name": "Northstar Capital" },
  "via": "key",
  "key": { "id": "2b7e…", "name": "CRM integration", "prefix": "cf_live_4f2a" }
}

Errors

StatusWhen
400A required parameter is missing.
401No API key, or the key is wrong or revoked.
422The state isn't covered for that check. The response lists the covered states.
502The state's records couldn't be reached. Clerkfield never answers with stale or guessed data instead.

Every error is JSON with an error message.

Usage and versions

Each business check and each lien search counts as one request; your profile in the app shows this month's requests by check and by state. Account and coverage calls aren't counted. Clerkfield is free while in beta.

Searches in states read live from the state's own website can take several seconds, because Clerkfield sends one request at a time to the state and waits for its answer. Set your HTTP timeout to at least 60 seconds.

The API is version 1: fields may be added, but existing fields won't be renamed or removed without a new version and advance notice.

MCP server for AI assistants

Use Clerkfield from Claude, Cursor, VS Code and other MCP clients. The three tools are verify_business, search_liens and get_coverage; they run the same checks as the API and count as the same requests.

Remote (no install): point your client at https://clerkfield.com/mcp (Streamable HTTP) and send your API key as Authorization: Bearer <key>.

Local: run the open-source package clerkfield-mcp with npx and your key in CLERKFIELD_API_KEY. Source: github.com/bramontiventures/clerkfield-mcp.

{
  "mcpServers": {
    "clerkfield": {
      "command": "npx",
      "args": ["-y", "clerkfield-mcp"],
      "env": { "CLERKFIELD_API_KEY": "cf_live_…" }
    }
  }
}

OpenAPI

The machine-readable description of every endpoint, for code generators, API clients and AI tools: ${SITE_URL.replace(/^https?:///, "")}/openapi.json (OpenAPI 3.1).

Frequently asked questions.

Straight answers. Still have a question?

Talk to us

  • Call it from your server. An API key gives full access to your account's checks, so it must never ship in a web page or a mobile app.

  • Not separately: every call runs a real search. While Clerkfield is in beta, calls are free, so test against real businesses in a covered state.

  • It means the state's records couldn't be reached at that moment. Retry after a short wait; Clerkfield never answers with stale or guessed data instead.