Kazuki Invoice Registration Verify for WooCommerce

Who this is for: WooCommerce shops that already collect 適格請求書発行事業者登録番号 (T + 13 digits) at checkout and want to know whether the number is really registered with Japan’s tax office—not just whether it looks like the right format.

What it does in plain terms:

When a customer enters a registration number, this plugin asks the National Tax Agency (NTA) public register whether that number is active. The result is saved on the order so you can see « valid » or « not found » in the admin. You can optionally block checkout if the number is not valid on the register.

This plugin does not add a checkout field. Install Kazuki Qualified Invoice Number for WooCommerce first (or use your own field that saves the same order data).

Typical workflow:

1. Install the registration number field plugin and enable the checkout field.

2. Apply for a free Application ID on the NTA website (often takes 1–2 months to arrive).

3. WooCommerce → Settings → 登録番号照合 — paste the Application ID.

4. Customer enters a number at checkout → plugin checks the NTA register automatically.

5. You see the verification result on the order (registered name when available).

What you need to know (no tax expertise required):

• Format vs. real registration — another plugin (or your theme) should check that the value looks like T + 13 digits. This plugin only checks the official public list.

• Without an Application ID — verification is skipped; checkout is not blocked.

• Caching — the same number is not queried on every page load (default: 24 hours).

• Works with classic checkout and WooCommerce Checkout Block fields from the Kazuki registration number plugin.

Works well with:

• Kazuki Qualified Invoice Number for WooCommerce — checkout field and format check

• Kazuki Accounting Export for WooCommerce — journal export for Yayoi; registration number in memo

Enjoying this plugin? If it helps your shop, a review on WordPress.org would mean a lot to us — thank you.

External services

This plugin connects to the National Tax Agency (NTA) Qualified Invoice Issuer Publication System Web-API to verify whether a registration number is valid on the public register.

• Service: NTA Invoice Issuer Publication System Web-API (number lookup endpoint).

• What is sent: Your NTA Application ID, the registration number to look up (T + 13 digits), and standard HTTP request metadata. Sent only when a customer enters a registration number at checkout (or when an order is saved with a number), and when the store owner has configured an Application ID.

• When: During WooCommerce checkout validation and when saving order verification metadata. Responses may be cached in the WordPress database for a configurable period (default 24 hours).

• Terms of service: Web-API terms of use, NTA publication site terms.

• Privacy policy: NTA personal information protection policy.

This service is provided by the National Tax Agency of Japan. Verification results are based on public register data; the NTA does not guarantee third-party services built on this API.