Kaisha — Japan Company Registry API日本の法人データを、AIエージェントが1コール数円で買えるAPI
Official-registry lookups for every registered Japanese corporation — including the only Japan invoice (適格請求書) number verification on x402. Pay per request with x402 — your agent's wallet is the account.
Endpoints
| Endpoint | What it does | Price |
|---|---|---|
GET /invoice/verify?number= | Unique on x402: qualified-invoice number (T+13) → registered / cancelled / not found against the NTA registry, registration date, corporate name. Essential for AP/expense agents processing Japanese receipts | $0.01 |
GET /companies/events | New: daily feed of newly registered companies (新設法人), closures, moves & renames from NTA diff data — the only x402 source for discovering new Japanese companies. Lead-gen ready | $0.01 |
GET /resolve?q= | Company name (fuzzy) or 13-digit corporate number → canonical name, address, entity type, active/closed | $0.005 |
GET /calendar/business-days | Business-day check / add N days / count range (weekends + national holidays) | $0.002 |
GET /calendar/holidays?year= | Japanese national holidays 1955–2027 (Cabinet Office) | $0.002 |
GET /sample | Exact output of every paid endpoint — try before you pay | free |
GET /catalog · GET /openapi.json · GET /llms.txt | Machine-readable service docs | free |
Quickstart — agents
# 1) See the 402 challenge
curl -i "https://kaisha-api.hp-vladic.workers.dev/resolve?q=%E3%83%88%E3%83%A8%E3%82%BF%E8%87%AA%E5%8B%95%E8%BB%8A"
# 2) Pay automatically with the x402 fetch wrapper (Base USDC)
import { x402Client, wrapFetchWithPayment } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm/exact/client";
const client = new x402Client();
client.register("eip155:*", new ExactEvmScheme(signer, { rpcUrl: "https://mainnet.base.org" }));
const fetchPay = wrapFetchWithPayment(fetch, client);
const res = await fetchPay("https://kaisha-api.hp-vladic.workers.dev/resolve?q=トヨタ自動車");Works with any x402 v2 client. Payments settle as USDC on Base (eip155:8453) or Solana mainnet — both offered in every 402 challenge.
Quickstart — MCP (Claude Code, OpenClaw, Cursor…)
claude mcp add kaisha -e EVM_PRIVATE_KEY=0x<base-wallet-with-usdc> -- npx -y kaisha-mcp5 tools: resolve_japanese_company / verify_japan_invoice_number / japan_business_days / japan_holidays / kaisha_catalog.
Data & privacy
Sources: National Tax Agency Corporate Number Publication Site & Qualified Invoice Issuer Publication Site (open data, refreshed monthly — see checkedAgainst in responses), Cabinet Office holiday dataset. Records flagged non-displayable by NTA are excluded; individual proprietors' names are never stored or returned.