# Kaisha — Japan Company Registry API for AI Agents

Official-data lookups for Japanese companies, including the ONLY Japan qualified-invoice (適格請求書) registration-number verification available over x402. Pay per call with x402 (USDC on Base eip155:8453 or Solana mainnet). No API keys, no signup — the paying wallet is the account.

Data: all 5,763,922 registered Japanese corporations + 5,050,531 qualified-invoice registrations, from the National Tax Agency open datasets (refreshed monthly). Individual proprietors' names are never returned.

## Endpoints
- GET https://kaisha-api.hp-vladic.workers.dev/companies/events?type=new[&days=7][&prefecture=][&kind=] — $0.01/call. Daily feed of Japanese corporate registry events from NTA diff data: newly registered companies (新設法人), closures, address changes, renames, mergers. The only x402 source for newly founded Japanese companies — built for lead-generation agents.
- GET https://kaisha-api.hp-vladic.workers.dev/resolve?q=<company name or 13-digit corporate number>[&prefecture=][&limit=] — $0.005/call. Resolve to corporate number, canonical name, head-office address, entity type, active/closed status. Fuzzy name normalization (legal forms, zenkaku/hankaku, kana).
- GET https://kaisha-api.hp-vladic.workers.dev/invoice/verify?number=T<13 digits> — $0.01/call. Verify a Japan qualified-invoice-issuer registration number: active/cancelled/not_found, registration date, corporate name, checksum validation.
- GET https://kaisha-api.hp-vladic.workers.dev/calendar/business-days?from=YYYY-MM-DD[&add=N|&to=YYYY-MM-DD] — $0.002/call. Japanese business-day check/add/count.
- GET https://kaisha-api.hp-vladic.workers.dev/calendar/holidays?year=YYYY — $0.002/call. National holidays 1955-2027.
- GET https://kaisha-api.hp-vladic.workers.dev/sample[?type=resolve|invoice|events|holidays|business-days] — FREE. The exact JSON shape every paid endpoint returns, as a static example. Call this first to check the output before spending anything.
- GET https://kaisha-api.hp-vladic.workers.dev/catalog — free machine-readable catalog. GET https://kaisha-api.hp-vladic.workers.dev/openapi.json — OpenAPI 3 spec.

## MCP
npx -y kaisha-mcp (env: EVM_PRIVATE_KEY=<Base wallet holding USDC>). Tools: resolve_japanese_company, verify_japan_invoice_number, japan_business_days, japan_holidays, kaisha_catalog.

## Payment
x402 v2. Every 402 challenge offers exact-scheme USDC on Base and Solana. Typical flow: request → 402 with PAYMENT-REQUIRED header → sign → retry with payment → 200 + PAYMENT-RESPONSE settlement proof.

## Sister service
Denpyo — Japan Invoice & Receipt Reader (https://denpyo-api.hp-vladic.workers.dev): OCR Japanese invoices (請求書) and receipts (領収書) into structured JSON with the same NTA qualified-invoice verification built in. MCP: npx -y denpyo-mcp.