Korea Business Verify (KBV) — MCP Server

KBV is a hosted MCP server that verifies Korean businesses in real time — 10 free calls/day, then pay-per-call (x402). Give it a 10-digit Korean business registration number (사업자등록번호) and it returns the registration status (active / suspended / closed), tax type, and — optionally — whether the number matches a representative name and opening date. Data comes live from the Korea National Tax Service (NTS) and is returned as clean, English-normalized JSON.

No account, no API key, no installation — connect any MCP-capable agent to one URL:

https://kbv-server-f7vfitmlkq-du.a.run.app/mcp

Built for AI agents and developers doing KYB / due-diligence on Korean companies: procurement, contracting, payments, marketplace onboarding.

Quick facts

Connect your agent

Claude (claude.ai)

1. Settings → Connectors → Add custom connector
2. URL: https://kbv-server-f7vfitmlkq-du.a.run.app/mcp
3. Enable the connector in a chat and ask: "Check the status of Korean business 124-81-00998."

Claude Code (CLI)

claude mcp add --transport http kbv https://kbv-server-f7vfitmlkq-du.a.run.app/mcp

ChatGPT

1. Settings → Connectors (requires a plan with connector / developer-mode support)
2. Add a custom MCP connector with URL https://kbv-server-f7vfitmlkq-du.a.run.app/mcp
3. Enable it in a conversation and ask about a Korean business number.

Cursor

Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "korea-business-verify": {
      "url": "https://kbv-server-f7vfitmlkq-du.a.run.app/mcp"
    }
  }
}

Any other MCP client

Use transport Streamable HTTP with the endpoint above. Clients must send Accept: application/json, text/event-stream (standard MCP clients do this automatically). Opening /mcp in a browser returns Method not allowed by design — browsers send GET, MCP uses POST. Use /health for a visual liveness check.

Tools

check_korean_business_status

Check the registration status of a Korean business by its 10-digit business registration number.

Input — hyphens/spaces allowed; normalized internally:

{ "business_number": "124-81-00998" }

Output (real example — Samsung Electronics):

{
  "business_number": "1248100998",
  "status": "active",
  "status_code_raw": "01",
  "tax_type": "general",
  "closed_date": null,
  "checked_at": "2026-08-24T10:08:20.082Z",
  "source": "Korea National Tax Service (NTS)",
  "cache": false
}

Field reference:

• status: active | suspended | closed | not_registered
• tax_type: general | simplified | exempt | non_profit | unknown
• closed_date: ISO date ("2023-01-31"), only for closed businesses, otherwise null
• checked_at: ISO 8601 UTC timestamp of the NTS query
• cache: true only when the NTS API was temporarily unavailable and a cached result (max 24 h old) was served; checked_at then reflects the original fetch time

A number that is well-formed but not registered with the NTS returns "status": "not_registered" (not an error).

check_korean_business_batch

Check up to 100 businesses in a single call — for screening supplier or customer lists without 100 round-trips.

Input:

{ "business_numbers": ["124-81-00998", "220-81-62517"] }

Output — one entry per input number (order preserved, same schema as above) plus a summary:

{
  "results": [
    { "business_number": "1248100998", "status": "active", "...": "..." },
    { "business_number": "2208162517", "status": "active", "...": "..." }
  ],
  "summary": { "total": 2, "active": 2, "suspended": 0, "closed": 0, "not_registered": 0 }
}

• The whole batch is answered with one upstream NTS query.
• Numbers checked within the last 24 hours may be served from cache (marked "cache": true with their original checked_at) and are excluded from the upstream query.
• More than 100 numbers, or any malformed number, is rejected before anything is queried.

verify_korean_business

Verify that a business registration number matches the provided representative name and opening date (KYB identity check), and get the current status in the same call.

Input:

{
  "business_number": "124-81-00998",
  "representative_name": "홍길동",
  "opening_date": "1969-01-13",
  "address": "경기도 수원시"
}

• representative_name and opening_date (YYYY-MM-DD) are required.
• address is optional and improves match precision.
• Names and addresses should be given as registered with the NTS (Korean script).

Output — same schema as above plus identity_match:

{
  "business_number": "1248100998",
  "status": "active",
  "status_code_raw": "01",
  "tax_type": "general",
  "closed_date": null,
  "checked_at": "2026-08-24T10:08:23.483Z",
  "source": "Korea National Tax Service (NTS)",
  "cache": false,
  "identity_match": false
}

identity_match is true only when the NTS confirms that the number, representative name, and opening date all match its records.

REST API

The same three operations are available as plain HTTP endpoints — same JSON schemas as the MCP tools, no auth. Append ?free=1 to use the daily free tier (10 lookups per IP per day); without the flag, unpaid requests return 402 with x402 payment requirements:

# Registration status (hyphens in the number are fine)
curl "https://kbv-server-f7vfitmlkq-du.a.run.app/v1/business/124-81-00998/status?free=1"

# KYB identity check
curl -X POST "https://kbv-server-f7vfitmlkq-du.a.run.app/v1/business/verify?free=1" \
  -H "Content-Type: application/json" \
  -d '{"business_number":"124-81-00998","representative_name":"홍길동","opening_date":"1969-01-13"}'

# Batch status check (up to 100 numbers)
curl -X POST "https://kbv-server-f7vfitmlkq-du.a.run.app/v1/business/batch?free=1" \
  -H "Content-Type: application/json" \
  -d '{"business_numbers":["124-81-00998","220-81-62517"]}'

HTTP status codes: 200 success (including cache-served results), 400 invalid input, 402 payment required (no ?free=1, or the daily free tier is exhausted — pay per call via x402), 503 NTS temporarily unavailable with no cached result.

Errors

Errors are returned as MCP tool errors (or REST 4xx/5xx responses) with a machine-readable JSON body:

Data source and license

• All data comes from the Korea National Tax Service (국세청) via the official Korean government open-data API (data.go.kr: 사업자등록정보 진위확인 및 상태조회 서비스), queried live on every request — KBV stores no business database.
• The underlying dataset is published under the Korean government open-data policy with no usage restrictions (이용허락범위: 제한 없음), so responses may be used commercially and cited freely.
• KBV normalizes the Korean-language, code-based NTS responses into the stable English JSON schema documented above; raw NTS payloads are never passed through.
• Freshness: queries hit the NTS registry directly. Newly registered businesses may take 1–2 business days to appear in the NTS system itself.

Privacy

• Query contents are never logged. Business numbers, representative names, and addresses appear in no server logs and are sent nowhere except the official NTS API that answers the query.
• Server logs contain only request counts, outcomes, and latency metrics.
• A short-lived in-memory cache (24 h max, hashed keys) exists solely so the service can answer during NTS outages; it is never shared or exported.

Pricing

• Free tier: 10 lookups per IP per day (a batch call counts one per number), resetting at 00:00 UTC. No account or key is needed. MCP tools use it automatically; REST calls opt in by appending ?free=1 — without the flag, REST answers 402 with x402 payment requirements. MCP and REST share the same counter.
• Beyond the free tier, the REST endpoints are pay-per-call via the x402 protocol (USDC on Base mainnet, agent-payable — no signup):
  • GET /v1/business/{number}/status — $0.02
  • POST /v1/business/verify — $0.05
  • POST /v1/business/batch — $0.02 per number (authorize up to $2.00, settled at actual usage)
• Over-quota MCP tool calls return a free_tier_exceeded error that points to the paid REST endpoints above.
• Fair use: the upstream NTS quota is shared; the free tier keeps light usage free while heavy traffic moves to paid calls.

FAQ

What is a Korean business registration number? A 10-digit identifier (사업자등록번호, often written 123-45-67890) issued by the Korea National Tax Service to every registered business in South Korea.

Can I check whether a Korean company is still operating? Yes — call check_korean_business_status; "status": "active" means the business is currently registered and operating, "closed" includes the closure date.

Can I verify a Korean company's identity before a transaction (KYB)? Yes — call verify_korean_business with the number, representative name, and opening date; identity_match: true means the NTS confirms all three match.

Can I screen a whole supplier list at once? Yes — check_korean_business_batch (or POST /v1/business/batch) takes up to 100 numbers per call and returns per-number results plus a summary.

Do I need an API key? No. Connect to the MCP URL and call the tools, or call the REST endpoints directly.

Self-hosting / development

The server is open for local development (Node.js ≥ 22, TypeScript, Express + official MCP SDK):

cp .env.example .env       # put your own data.go.kr DECODING key in NTS_SERVICE_KEY
npm install
npm run dev                # → http://localhost:8080  (MCP at /mcp)
npm test                   # vitest, upstream fully mocked — no network

Deployment guide (Google Cloud Run): see DEPLOY.md. Architecture and design spec: DESIGN.md.