Japanese residents need a way to use their physical My Number Cards for digital authentication on various government web portals (e-tax, local government services, etc.) through Chrome. The extension acts as a communication bridge between government web pages and the native My Number Card reader application.

User visits a government service website → the website detects the extension via a hidden input element → the website dispatches a 'launchApp' custom event → the content script forwards this to the background service worker → the service worker connects to the native 'jp.go.cao.mpa' messaging host → the native app communicates with the physical card reader to read the My Number Card and request PIN → authentication result is returned through the chain back to the government website.

Target users: Japanese residents who need to authenticate with online government services using their My Number Card / Users filing taxes, applying for certificates, or accessing local government online portals in Japan

Extension is very small (4 text files, ~8KB of source), making analysis straightforward
The native host application (jp.go.cao.mpa) source is not included and is distributed separately via a dedicated installer, so its internals cannot be verified
No popup UI exists — the extension operates entirely as a content script + background service worker bridge

Monetization

No paid features detected

No evidence of any paid features, payment platforms, subscriptions, or premium tiers in the extension code. This is a government-provided (内閣府 / Cabinet Office) free tool for enabling My Number Card authentication on government services. The 'pro' keyword hit is only in verified_contents.json metadata and is unrelated to payment.

Confidence: 95
Payment platform: --
Source: AI / High
Login required: Yes
Reason: The extension is a bridge that enables My Number Card (マイナンバーカード) authentication on Japanese government online services. The extension itself has no login UI, but its core workflow requires the user to authenticate via a physical My Number Card + PIN on destination government services (e.g., *.go.jp tax portals, local government sites). The native host app 'jp.go.cao.mpa' handles the card reader interaction, and the government websites require My Number Card-based identity verification to complete any workflow.

Permission risk

High-risk permissions

This estimate uses declared permissions and host permissions to assess access scope and sensitivity.

敏感权限：nativeMessaging

Publisher

デジタル庁

マイナポータルアプリ

Email: [email protected]
Phone: --
Address: --

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Permissions

Host access

マイナポータル

マイナポータル Media preview

30-day user trend

User Growth Over Time

30-day rating change

30-day rating change

Daily, weekly, and monthly growth

Version, languages, and crawl freshness

Product summary

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