Invoice OCR & Tax Invoice Checker

**Invoice Checker — Instantly Verify Japanese Invoice Registration Numbers**

Invoice Checker automatically scans any web page for Japanese consumption tax invoice registration numbers (T + 13 digits) and verifies them against the National Tax Agency (NTA) official API in real time.

**Key Features**

- **Auto-detection**: Scans the current page for invoice registration numbers as you browse, including PDF viewer pages
- **Instant verification**: Checks each number against Japan's official NTA registry (web-api.invoice-kohyo.nta.go.jp)
- **Visual highlights**: Valid numbers turn green; invalid numbers turn red — right on the page
- **Manual lookup**: Enter any number directly in the popup for on-demand verification
- **Verification history**: Review past checks with business name, address, and registration dates
- **24-hour cache**: Repeat lookups are served instantly without hitting the API again
- **Freemium**: 10 free verifications per month; upgrade to Pro for unlimited checks ($6.49/mo)

**How to Use**

1. Install the extension
2. Navigate to any web page containing invoice numbers (e.g., invoices, quotations, purchase orders)
3. Numbers matching the T + 13-digit pattern are automatically highlighted
4. Click the extension icon to see a list of detected numbers with their verification status
5. Use the manual input field to verify any number on demand

**Perfect for**
- Accounting and bookkeeping professionals
- Small business owners handling Japanese invoices
- Procurement teams verifying vendor registration

**Privacy & Data**
- No personal data is collected or stored on external servers
- Invoice numbers are sent only to the official NTA API (web-api.invoice-kohyo.nta.go.jp) for verification
- All data is stored locally in your browser using chrome.storage.local
- No tracking, no ads, no third-party analytics beyond anonymous usage stats