Korea Business Verify (KBV)

Korea Business Verify (KBV) — MCP Server

[M8ven Score]

KBV is a hosted MCP server that finds and verifies Korean businesses in real time — 10 free calls/day, then pay-per-call (x402).

You only need the company name. Search "Samsung Electronics" — in English or Korean — and KBV returns the matching companies with their 10-digit business registration numbers (사업자등록번호), ranked by confidence. That matters because every other Korean business API assumes you already have the number, which a foreign agent almost never does. The index covers 940,000 companies: every DART disclosure filer (with English names) plus every vendor registered for public procurement, so small businesses are in it too, not just conglomerates.

With a number in hand, KBV returns 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

find_korean_business

Find a company by name when you do not know its registration number — the starting point for everything else here.

Input:

{ "name": "Samsung Electronics" }

Output (real example, abbreviated) — candidates, never one confident guess:

{  "query": "Samsung Electronics",  "candidates": [    {      "business_number": "1248100998",      "name": "삼성전자",      "name_en": "SAMSUNG ELECTRONICS CO,.LTD",      "confidence": 1,      "match": { "type": "exact", "field": "name_en" },      "evidence": { "status": "active", "tax_type": "general", "listed": true }    },    {      "business_number": "6178117517",      "name": "삼성전자판매",      "confidence": 0.75,      "match": { "type": "prefix", "field": "name" },      "evidence": { "status": "active", "tax_type": "general", "listed": false }    }  ],  "note": "4 companies match this name equally well; they are distinct legal entities. Compare the evidence fields before acting."}

• Korean or English. Legal-form noise is ignored: Samsung Electronics, SAMSUNG ELECTRONICS CO,.LTD and 삼성전자(주) all match the same company.
• confidence reflects how the name matched (exact > prefix > contains), nudged by source and listing status. match tells you which field matched, so the score is never a black box.
• evidence is what separates similarly named companies: live registration status, tax type, region (city/district), and whether the company is listed.
• A name can be ambiguous — "Samsung Electronics" legitimately matches four distinct legal entities. KBV returns them all with a note rather than picking one.
• No match returns candidates: [] with a note saying so. That is an answer, not an error: a lookup failure returns HTTP 503 with an error field instead.

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:

# Find a company by name — the free tier returns names, numbers and confidencecurl -G "https://kbv-server-f7vfitmlkq-du.a.run.app/v1/business/search" \  --data-urlencode "q=Samsung Electronics" --data-urlencode "free=1"
# 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 checkcurl -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

• KBV's own logs never contain query contents. The service writes only event counts, outcomes, and latency; business numbers, representative names, and addresses are never written to them, and are sent nowhere except the official NTS API that answers the query.
• One exception, inherent to HTTP: GET /v1/business/{number}/status carries the business number in the URL path, so it appears in the platform access log that Google Cloud Run records for every request. Those entries are retained for 14 days, then deleted automatically. KBV cannot mask a single field inside them: Cloud Logging filters whole entries, it does not rewrite them.
• Not affected: POST /v1/business/verify, POST /v1/business/batch and all MCP tool calls send their inputs in the request body, which access logs do not record. Prefer these if you would rather no identifier appear in any log.
• For context, a Korean business registration number is a public company identifier rather than personal data — though a sole proprietorship is registered to an individual, so the distinction above is worth knowing.
• 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.
• Finding is free, confirming is paid. GET /v1/business/search?q=…&free=1 returns names, business numbers and confidence within the free tier — an agent that only knows a company name can always reach a number. The paid call adds the evidence fields (status, tax type, region, listing) that separate similarly named companies.
• 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/search — $0.02 (candidates with evidence)
  • 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

I only know the company's name — can I still use this? Yes, and that is the point of find_korean_business (or GET /v1/business/search). Give it a name in English or Korean and it returns the matching companies with their registration numbers, ranked by confidence. Every other tool here needs the number; this is how you get it.

Does name search cover small companies, or only conglomerates? Both. The index combines DART disclosure filers (~119k, nearly all with English names) with every vendor registered for public procurement (~821k), which is where small and mid-sized Korean companies appear.

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_KEYnpm installnpm 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.