# KnowFirm

> KYB (Know Your Business) & firmographic data API. Verify, enrich, and sanctions-screen any U.S.
> business by EIN, name, LEI, or CIK in one call — resolved across authoritative public sources with
> confidence scores and per-field provenance. Developer-first, self-serve, usage-priced.
> Not an FCRA consumer product (not for credit, employment, insurance, or housing eligibility).

Base URL: https://api.knowfirm.com
Auth: API key in the `X-API-Key` request header (or `Authorization: Bearer <key>`).

## API
- GET /v1/business — Resolve one business by `ein`, `lei`, `cik`, `cert` (FDIC certificate), `ticker`
  (SEC exchange ticker), or `name` → canonical entity with identifiers (LEI/CIK/EIN/FDIC cert/ticker),
  type, contributing sources, confidence, firmographics, and per-field provenance.
- GET /v1/business/search — Search businesses by normalized name (exact + prefix extensions, e.g. "verizon" finds Verizon Communications) → ranked candidates. Typo-tolerant: trigram fuzzy matching recalls the entity even from a misspelled query (e.g. "jpmorgn").
- POST /v1/screening — Sanctions / denied-party screening against the U.S. Consolidated Screening List
  (informational; verify potential matches against the official source before acting).
- POST /v1/enrich — Batch resolve up to 100 businesses in one request (billed per record).
- GET /v1/segments/preview — Discover: count + first 25 rows of a filtered firm segment (Form 5500
  plan sponsors, FDIC banks, NCUA credit unions, FMCSA carriers, IRS nonprofits) by state / size / industry /
  filing recency. Firm-level records only — no personal contact data.
- POST /v1/segments/export — Discover: export segment rows (billed per row; limit ≤ 10,000).
  Prospecting / account-intelligence use — not for FCRA-covered eligibility decisions.
- GET /v1/health — Health check (free, unmetered).

## Docs
- Quickstart: https://knowfirm.com/docs
- Interactive playground: https://knowfirm.com/playground
- OpenAPI spec: https://knowfirm.com/openapi.yaml
- Terms: https://knowfirm.com/legal/terms-of-service
- Sources & attribution: https://knowfirm.com/legal/data-sources-attribution

## Guides
- What is a KYB API: https://knowfirm.com/learn/kyb-api
- Verify a business by EIN: https://knowfirm.com/learn/verify-a-business-by-ein
- Sanctions screening API: https://knowfirm.com/learn/sanctions-screening-api
- KYB vs KYC: https://knowfirm.com/learn/kyb-vs-kyc
- LEI lookup API: https://knowfirm.com/learn/lei-lookup-api

## About
KnowFirm is a product of persoon.ai. Self-serve with a free tier; usage-priced as you grow.
KYB / firmographic data only — not a consumer-reporting product, and not for FCRA-covered eligibility
decisions (credit, employment, insurance, housing).

## Data sources
GLEIF (LEI, CC0), SEC EDGAR (public domain), IRS (public record), FDIC/NCUA, DOL Form 5500, and the
U.S. Consolidated Screening List. KnowFirm publishes resolved, value-added entity data with provenance.