Hera Japan Postcode Autofill for WooCommerce

Hera Japan Postcode Autofill for WooCommerce fills in the prefecture, city and street of a Japanese address as soon as the customer types the 7-digit postcode. It works on the Checkout block, on the classic checkout and on the address form under My account, for billing and shipping addresses alike.

This is an independent plugin, not affiliated with, endorsed by, or sponsored by WooCommerce or Automattic. WooCommerce is a trademark of Automattic Inc.

When the country of an address is Japan, WooCommerce already asks for the postcode before the prefecture, city and street. A Japanese postcode settles most of what comes after it, so the customer types seven digits and checks the result instead of typing the address out. The plugin works for any store that ships to Japan, whatever language the store itself uses.

Features

• The prefecture (WooCommerce’s state field), the city and the street are filled in as soon as the seventh digit is typed.
• Works with the Checkout block, the classic checkout and My account > Addresses.
• Never overwrites a street the customer typed. When the postcode changes, the prefecture and city follow it, and what the plugin filled in is cleared again if the postcode is no longer complete.
• Accepts full-width digits such as １００－０００１ and rewrites them as 100-0001, the form WooCommerce accepts, as soon as all seven are in.
• Fills in only what the postcode settles. A postcode shared by several towns leaves the street empty, and one shared by two cities leaves the city empty, instead of guessing.
• Covers about 143,000 postcodes, including those Japan Post assigns to a single large business, which fill in the street number as well.
• Acts only on addresses whose country is Japan. Addresses in other countries work as before.
• Tells screen reader users when it has filled in an address.
• Nothing to configure: no settings screen and no database tables.

No external connections

The postcode data ships inside the plugin, in one small file for each set of first three digits. When a customer types a postcode, the browser loads that one file from your own site. Nothing is sent to Japan Post or to any other service, no remote script is loaded, and the plugin stores nothing.

Postcode data

The data comes from the postcode files Japan Post publishes for addresses and for large businesses, in the release of 30 September 2026. Japan Post states that it does not claim copyright on this data and that anyone may redistribute it: https://www.post.japanpost.jp/service/search/zipcode/download/utf-readme.html. Plugin updates bring newer data, and the changelog names the release each version carries.

Documentation

The user guide is at herapress.com/docs.

Support

Use the support forum on this plugin’s WordPress.org page. Please say which postcode you typed, whether your store uses the Checkout block or the classic checkout, and which WordPress and WooCommerce versions it runs.