# SOSfinder

> Secretary of State business entity data for all 50 US states behind one
> simple API. Search any state's business registry through a single REST
> endpoint — entity status, registered agent, formation date, officers,
> addresses, and filing history — normalized into one consistent schema.
> Includes business-entity monitoring (scheduled re-checks with a change
> feed) and free SEO tools like the business name checker.

SOSfinder is an API-first product. Sign up at https://sos-finder.vercel.app/signup
for an instant API key (50 free lookups/month, no credit card). Plans:
Free ($0, 50 lookups/mo), Pro ($29, 10,000), Scale ($99, 50,000).
Support: support@sosfinder.com

## For AI agents: MCP server

The fastest way for an AI agent to use SOSfinder is the hosted Model Context
Protocol server (Streamable HTTP, stateless):

- Endpoint: https://api.sosfinder.com/mcp
- Auth: `Authorization: Bearer sos_live_…` (an account API key)
- Tools: search_business_entity, list_supported_states, list_monitors,
  create_monitor, delete_monitor, get_changes
- Setup guide: https://sos-finder.vercel.app/docs/mcp

Each search_business_entity call consumes one lookup credit; the other tools
are free.

## REST API

- Base URL: https://api.sosfinder.com
- Auth: `x-api-key` header or `Authorization: Bearer sos_live_…`
- GET /search?state=FL&business_name=Acme%20LLC — unified entity search;
  returns bestMatch plus similar results in one fixed envelope for all states
- POST/GET/PATCH/DELETE /v1/monitors — manage entity monitors
- GET /v1/changes?since={cursor} — account-wide change feed

## Docs

- [Introduction & quickstart](https://sos-finder.vercel.app/docs)
- [Authentication](https://sos-finder.vercel.app/docs/authentication)
- [Entity search reference](https://sos-finder.vercel.app/docs/entity-search)
- [API credits & billing](https://sos-finder.vercel.app/docs/api-credits)
- [Rate limits](https://sos-finder.vercel.app/docs/rate-limits)
- [Status codes](https://sos-finder.vercel.app/docs/status-codes)
- [MCP server](https://sos-finder.vercel.app/docs/mcp)

## Website

- [Pricing](https://sos-finder.vercel.app/pricing)
- [Free tools (business name checker, …)](https://sos-finder.vercel.app/tools)
- [Blog](https://sos-finder.vercel.app/blog)
- [Dashboard (sign in)](https://sos-finder.vercel.app/login)

## Coverage

31 states + DC live today, more added over time: AL, AR, CA, CO, DE, DC, FL,
GA, ID, IA, KS, KY, ME, MA, MS, MO, MT, NV, NH, NJ, NM, NY, ND, RI, SD, TX,
UT, VT, VA, WV, WI, WY. Call the list_supported_states MCP tool (or check
the docs) for the current list.

SOSfinder is not affiliated with any government agency.