# Japan public-data APIs for AI agents

Stop scraping Japanese government and public-data sites. Let your AI agent
call clean Japan payroll, company, and grant APIs over a single host.

Preview free. Trial key free. Production pay-per-call.

Try one preview call right now (no wallet, no signup):

```bash
curl -sS "https://api.kasanegi.com/preview/v1/local/combined/payroll-summary?monthly_salary=300000&year_month=2026-05"
```

Or browse all three products at https://api.kasanegi.com/products.

## Products

### 1. JP Local Pack — Japan payroll, invoice, tax, holiday, and corporate-lookup numbers without scraping NTA, gBizINFO, MHLW, or Cabinet Office.

Get clean Japan payroll deductions, social-insurance grades, consumption-tax rates, national holidays, and corporate-number lookups in one call.

Best first preview call (free, no wallet, no signup):

```bash
curl -sS "https://api.kasanegi.com/preview/v1/local/combined/payroll-summary?monthly_salary=300000&year_month=2026-05"
```

Returns: Japan monthly payroll combo: deductions + social insurance + holiday + tax in one call..

Paid production paths after preview (= pick the channel that fits the buyer):

- Marketplace / API-key path (= human / normal-developer buyer pays the
  marketplace by card or platform credit; status: public marketplace listing live at https://rapidapi.com/kasanegi123/api/jp-local-pack-japan-payroll-invoice-tax-apis):

  ```bash
  # End buyers should use the published marketplace listing, not curl this
  # origin path directly. The marketplace proxy injects the shared secret.
  curl -i \
    -H "X-Kasanegi-Marketplace-Secret: <set-by-marketplace-proxy>" \
    "https://api.kasanegi.com/marketplace/rapidapi/v1/local/combined/payroll-summary?monthly_salary=300000&year_month=2026-05"
  ```

- x402 direct micropayment (= optional, for agent-native buyers; USDC on
  Base mainnet):

  ```bash
  # 402 without X-PAYMENT; settle and retry with X-PAYMENT (open x402 protocol).
  curl -i "https://api.kasanegi.com/v1/local/combined/payroll-summary?monthly_salary=300000&year_month=2026-05"
  ```

Pricing: $0.001 to $0.020 USDC per call.

Example output (truncated):

```json
{
  "monthly_salary": 300000,
  "year_month": "2026-05",
  "income_tax_jpy": 6850,
  "health_insurance_jpy": 14760,
  "pension_jpy": 27450,
  "employment_insurance_jpy": 1800,
  "net_pay_jpy": 249140,
  "_attribution": "NTA / MHLW / Kyokai Kenpo (public official sources)"
}
```

### 2. JP Data Enrich — Resolve a Japanese company name, domain, or 13-digit corporate number into structured corporate, gBizINFO, EDINET, and signal data.

Turn a messy Japanese company string into ranked candidates with corporate number, legal name, address, EDINET filings, and a numeric match-reliability score.

Best first preview call (free, no wallet, no signup):

```bash
curl -sS "https://api.kasanegi.com/preview/v1/enrich/company-by-name?name=%E3%83%88%E3%83%A8%E3%82%BF%E8%87%AA%E5%8B%95%E8%BB%8A"
```

Returns: Japan company candidate resolution from name (= 5-mode disambiguation)..

Paid production paths after preview (= pick the channel that fits the buyer):

- Marketplace / API-key path (= human / normal-developer buyer pays the
  marketplace by card or platform credit; status: public marketplace listing live at https://rapidapi.com/kasanegi123/api/jp-local-pack-japan-payroll-invoice-tax-apis):

  ```bash
  # End buyers should use the published marketplace listing, not curl this
  # origin path directly. The marketplace proxy injects the shared secret.
  curl -i \
    -H "X-Kasanegi-Marketplace-Secret: <set-by-marketplace-proxy>" \
    "https://api.kasanegi.com/marketplace/rapidapi/v1/enrich/company-by-name?name=%E3%83%88%E3%83%A8%E3%82%BF%E8%87%AA%E5%8B%95%E8%BB%8A"
  ```

- x402 direct micropayment (= optional, for agent-native buyers; USDC on
  Base mainnet):

  ```bash
  # 402 without X-PAYMENT; settle and retry with X-PAYMENT (open x402 protocol).
  curl -i "https://api.kasanegi.com/v1/enrich/company-by-name?name=%E3%83%88%E3%83%A8%E3%82%BF%E8%87%AA%E5%8B%95%E8%BB%8A"
  ```

Pricing: $0.010 to $0.050 USDC per call.

Example output (truncated):

```json
{
  "candidates": [
    {
      "corporate_number_hint": "<13-digit corporate number>",
      "legal_name": "<resolved legal name>",
      "match_reliability": 0.98,
      "match_reliability_label": "high",
      "_source": "gBizINFO + brand alias map"
    }
  ]
}
```

### 3. JP Grants — Japan grants discovery, deadlines, detail, and review-required eligibility candidates from J-Grants and Mirasapo Plus.

Surface Japan public-grant opportunities, structured deadlines, contact info, and amount-extraction safety so an agent can shortlist candidates for human review.

Best first preview call (free, no wallet, no signup):

```bash
curl -sS "https://api.kasanegi.com/preview/v1/grants/detail?id=a0WJ200000CDYZ2MAP"
```

Returns: Single-grant detail with structured fields, deadline, contact, and amount-extraction safety..

Paid production paths after preview (= pick the channel that fits the buyer):

- Marketplace / API-key path (= human / normal-developer buyer pays the
  marketplace by card or platform credit; status: public marketplace listing live at https://rapidapi.com/kasanegi123/api/jp-local-pack-japan-payroll-invoice-tax-apis):

  ```bash
  # End buyers should use the published marketplace listing, not curl this
  # origin path directly. The marketplace proxy injects the shared secret.
  curl -i \
    -H "X-Kasanegi-Marketplace-Secret: <set-by-marketplace-proxy>" \
    "https://api.kasanegi.com/marketplace/rapidapi/v1/grants/detail?id=a0WJ200000CDYZ2MAP"
  ```

- x402 direct micropayment (= optional, for agent-native buyers; USDC on
  Base mainnet):

  ```bash
  # 402 without X-PAYMENT; settle and retry with X-PAYMENT (open x402 protocol).
  curl -i "https://api.kasanegi.com/v1/grants/detail?id=a0WJ200000CDYZ2MAP"
  ```

Pricing: $0.020 to $0.050 USDC per call.

Example output (truncated):

```json
{
  "grant_id": "<j-grants-id>",
  "title": "<grant title>",
  "deadline_date": "<YYYY-MM-DD>",
  "max_subsidy_amount_jpy": "<integer or null>",
  "amount_extraction_status": "ok | ambiguous_upstream | unknown",
  "data_completeness_score": 0.82,
  "_attribution": "Digital Agency J-Grants PDL 1.0"
}
```

## What we do not promise

- Sources are public official or public-registry sources only (J-Grants,
  gBizINFO, EDINET, NTA, Cabinet Office, MHLW, Kyokai Kenpo). No private
  or pre-disclosure data.
- Outputs are reference data or review-required candidates. We do not
  give legal, payroll, KYB, tax, or grant-eligibility final decisions.

## Sales channels (= production paid paths)

x402 is **one** option, not the only one. Production access is not gated
on holding crypto.

- Marketplace / API-key path (RapidAPI-class provider proxy): pay the
  marketplace by card or platform credit when the product has a public
  listing; the marketplace proxies the request to
  `https://api.kasanegi.com/marketplace/rapidapi/v1/...`. One public marketplace listing is live for all current products at https://rapidapi.com/kasanegi123/api/jp-local-pack-japan-payroll-invoice-tax-apis.
- x402 direct micropayment: settle USDC on Base mainnet per call. For
  agent-native buyers.
- Card / fiat checkout (Stripe / Polar / equivalent): not yet wired.
  Owner must create the merchant account and configure pricing.
- Wallet-free preview at `https://api.kasanegi.com/preview/v1/...` (= evaluation only,
  not a paid path).

Full machine manifest at `https://api.kasanegi.com/products` (`sales_channels`).

## Developers and agents

- Trial key (no wallet, no signup): `POST https://api.kasanegi.com/keys/create`
- Metered trial call: `POST https://api.kasanegi.com/broker/call` with `X-API-Key`
- Product catalog JSON: https://api.kasanegi.com/products
- OpenAPI 3.1: https://api.kasanegi.com/openapi.json
- LLM guide: https://api.kasanegi.com/llms.txt
- Marketplace proxy origin (RapidAPI base URL): https://api.kasanegi.com/marketplace/rapidapi/v1
- x402 auto-discovery: https://api.kasanegi.com/.well-known/x402
- x402scan-compatible alias: https://api.kasanegi.com/supported
- MCP gateway for agents: https://mcp.kasanegi.com/mcp
- Buyer feedback schema: https://api.kasanegi.com/feedback/schema

## Canonical buyer paths (= generated from product-contract registry)

The buyer-facing HTML at the top of this page lists the three current
products with one preview and one paid path each. The exhaustive
endpoint list — every preview path, every production path, and per-call
price — is auto-generated below for LLM and agent readers:

### JP Local Pack

Canonical preview path: `/preview/v1/local/{endpoint}` (= wallet-free, single host)
Canonical production path: `/v1/local/{endpoint}` (= x402 USDC on Base; 402 without X-PAYMENT, settle + forward on X-PAYMENT)

Sold endpoints:

- `/preview/v1/local/combined/payroll-summary` → Japan monthly payroll combo: deductions + social insurance + holiday + tax in one call. (= $0.015 USDC). Limit: Reference calculation only; not final payroll, tax, or filing advice.
- `/preview/v1/local/payroll/calc-by-salary` → Japan payroll deduction calc by monthly salary: tax + social insurance. (= $0.010 USDC). Limit: Reference calculation only.
- `/preview/v1/local/social-insurance/standard-remuneration` → Japan standard-remuneration grade lookup from monthly salary. (= $0.010 USDC). Limit: Reference grade only.
- `/preview/v1/local/tax/consumption/rate` → Japan consumption tax rate (= invoice system aware) lookup by date. (= $0.001 USDC). Limit: Reference rate only.
- `/preview/v1/local/holiday/jp` → Japan national holiday list for a given year (2024-2027). (= $0.001 USDC). Limit: Coverage 2024-2027 only.
- `/preview/v1/local/houjin-lookup/by-name` → Japan corporate-number candidate lookup from company name (= 5-mode disambiguation). (= $0.020 USDC). Limit: Candidate ranking; not authoritative legal-name verification.
- `/preview/v1/local/houjin-number/lookup` → Japan corporate profile by 13-digit corporate number (= gBizINFO live). (= $0.010 USDC). Limit: gBizINFO-derived profile.
- `/preview/v1/local/invoice/issuer-by-name` → Qualified invoice issuer (T-number) candidate lookup by company name. (= $0.020 USDC). Limit: Candidate T-number with NTA registration_status=unverified until NTA Web-API ID is configured.
- `/preview/v1/local/invoice/issuer-registration-lookup` → Qualified invoice issuer registration lookup by T-number. (= $0.005 USDC). Limit: registration_status=unverified pending NTA API ID.
- `/preview/v1/local/invoice/peppol-validate` → Peppol BIS invoice XML validation (= 100KB body cap). (= $0.010 USDC). Limit: Body cap 100KB; reference validation only.

### JP Data Enrich

Canonical preview path: `/preview/v1/enrich/{endpoint}` (= wallet-free, single host)
Canonical production path: `/v1/enrich/{endpoint}` (= x402 USDC on Base; 402 without X-PAYMENT, settle + forward on X-PAYMENT)

Sold endpoints:

- `/preview/v1/enrich/company-by-name` → Japan company candidate resolution from name (= 5-mode disambiguation). (= $0.020 USDC). Limit: Candidate discovery; not legal identity verification.
- `/preview/v1/enrich/company-by-domain` → Japan company resolution from web domain (= ~40% coverage). (= $0.010 USDC). Limit: Coverage ~40%; non-resolved cases return match_type=not_found.
- `/preview/v1/enrich/company-by-houjin-number` → Japan company profile from 13-digit corporate number (= gBizINFO live). (= $0.010 USDC). Limit: NTA Corporate Number DB cross-check pending.
- `/preview/v1/enrich/business-signals-by-houjin` → Public-procurement and gazette signals by corporate number. (= $0.050 USDC). Limit: Public-source signals only; not financial advice.
- `/preview/v1/enrich/edinet-filings` → EDINET regulatory filings list by EDINET code. (= $0.050 USDC). Limit: Public EDINET filings only.
- `/preview/v1/enrich/people-by-houjin` → Listed-company officers (= EDINET annual-report rows) by corporate number. (= $0.010 USDC). Limit: Listed companies only via EDINET annual report.
- `/preview/v1/enrich/batch` → Batch company enrichment from name/domain/houjin (mixed, max 10 items). (= $0.050 USDC). Limit: Max 10 items per batch; same per-item caveats.

### JP Grants

Canonical preview path: `/preview/v1/grants/{endpoint}` (= wallet-free, single host)
Canonical production path: `/v1/grants/{endpoint}` (= x402 USDC on Base; 402 without X-PAYMENT, settle + forward on X-PAYMENT)

Sold endpoints:

- `/preview/v1/grants/detail` → Single-grant detail with structured fields, deadline, contact, and amount-extraction safety. (= $0.020 USDC). Limit: Review-required candidate triage; not a final eligibility determination.
- `/preview/v1/grants/search` → Grant search by keyword + filters (keyword optional, default any). (= $0.050 USDC). Limit: Review-required candidate list; final eligibility from official guidance.
- `/preview/v1/grants/upcoming` → Grant deadline calendar within N days (= 1-90, default 90). (= $0.050 USDC). Limit: Calendar precision SLA capped at 90 days.
- `/preview/v1/grants/eligible` → Grant ranking for company profile (= 5-factor weighted; review-required). (= $0.050 USDC). Limit: Review-required candidate triage; not a final eligibility determination.

Not for sale yet: grants-history.

Trial flow:

```bash
curl -sS -X POST "https://api.kasanegi.com/keys/create" \
  -H "content-type: application/json" \
  -d '{"owner_label":"my-team"}'

curl -sS -X POST "https://api.kasanegi.com/broker/call" \
  -H "X-API-Key: <key-from-step-1>" \
  -H "content-type: application/json" \
  -d '{"product_id":"jp-local-pack-v1-combined-payroll-summary","query":{"monthly_salary":300000,"year_month":"2026-05"}}'
```

MCP client config:

```json
{
  "mcpServers": {
    "mdaf": {
      "url": "https://mcp.kasanegi.com/mcp",
      "transport": "http"
    }
  }
}
```

Builder: MatsushitaTokitsugu, Japan. The host at https://api.kasanegi.com is the
single buyer integration target. It supports preview, marketplace
API-key, and x402 direct production calls; pick the path that fits the
buyer.

Discovery: https://api.kasanegi.com/.well-known/broker-manifest.json,
https://api.kasanegi.com/products, https://api.kasanegi.com/openapi.json, https://api.kasanegi.com/llms.txt,
https://api.kasanegi.com/feedback/schema.