Japan Invoice Verification: Qualified Invoice (T-Number) API for AI Agents

Japan's Qualified Invoice System (適格請求書制度), live since October 2023, requires real-time verification of T-prefixed 13-digit issuer numbers against the National Tax Agency (NTA) registry. Wrong validation = real tax liability. The official NTA API requires individual registration (1+ month wait); Torify is a drop-in alternative that works today.

Endpoint

GET https://torify.dev/v1/invoice/verify

Parameters

Name	Type	Required	Description	Example
`number`	string	Yes	T-prefixed 13-digit qualified invoice issuer number	`T8010401050783`

Response example

{
  "ok": true,
  "data": {
    "number": "T8010401050783",
    "registered": true,
    "registrantName": "...",
    "confidence": 0.99,
    "verifiedAt": "2026-05-11T08:00:00.000Z"
  }
}

Code examples

curl

curl "https://torify.dev/v1/invoice/verify?number=T8010401050783"

TypeScript (x402-fetch)

import { wrapFetchWithPayment } from 'x402-fetch';
import { privateKeyToAccount } from 'viem/accounts';

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const fetchWithPayment = wrapFetchWithPayment(fetch, account);

const res = await fetchWithPayment(
  'https://torify.dev/v1/invoice/verify?number=T8010401050783'
);
const data = await res.json();
console.log(data); // { ok: true, data: { ... } }

Python (requests)

import requests

# Free MCP tier (no auth) or API key (X-API-Key header)
res = requests.get(
    "https://torify.dev/v1/invoice/verify?number=T8010401050783",
    headers={"X-API-Key": "your_torify_pro_key"}
)
print(res.json())

Use cases

Subscription billing platform validating Japan customer T-numbers

Chargebee, Paddle, Stripe Billing, and similar platforms need to verify B2B customer T-numbers before issuing qualified invoices. Wrong T-number = tax filing rejection.

AP automation agent processing supplier invoices

An AI agent reading scanned invoices needs to verify the supplier's T-number is actually registered and matches the company name. Torify returns both registered status and registrant name in one call.

CRM customer onboarding flow

When a Japanese B2B customer signs up, the CRM (HubSpot, Pipedrive, Salesforce) auto-verifies their T-number to flag invalid or cancelled registrations early.

Edge cases & gotchas

T-number check digit uses coefficients [2,1,2,1,2,1,2,1,2,1,2,1] — reverse-order traversal. Wrong coefficient order = real NTT Docomo / 国税庁 T-numbers fail validation.
NTA registry has cancelled and transitional T-numbers. Torify returns confidence: 0.99 for active, 0.5 for cancelled, 0 for not found.
The official NTA API requires INVOICE_APP_ID registration (1+ month wait). Torify works without registration.

Related endpoints

/v1/invoice/validate — Japan Invoice Number Format Validation API
/v1/tax/calculate — Japan Consumption Tax Calculation API
/v1/eltax/check — Japan Electronic Bookkeeping Compliance API
/v1/houjin/lookup — Japanese Corporate Number Lookup: Houjin Bangou (法人番号) API

← All 36 endpoints

Pricing

$0.02 per call via x402 (USDC on Base). Or use a Pro API key ($49/mo, 10,000 calls/month).

View pricing Code examples ↗