Privacy Policy
Last reviewed: Jul 28, 2026
TaxNinja JP is a document-preparation tool for foreign residents of Japan. This policy explains what personal information we handle, why we use it, how long we keep it, and the rights you have.
1. What we collect
We handle account basics (email, name, hashed password), tax-return inputs (residency, postal code, amounts, ledger and receipt details), and technical logs such as IP, user-agent, and timestamps. The current public version does not retain a reusable My Number value as part of normal account data.
2. Why we use it
Only to generate your tax-return package and operate the service. We do not sell, rent, advertise with, or profile your data. When tax law or deduction tables update, we may recompute and display or regenerate derived figures from your stored inputs (your entered data itself is never altered).
3. How long we keep it
Tax-year records stay until you delete them. Generated PDFs are rendered on demand and not retained server-side. AI chat history is purged after 30 days. Security and audit logs are retained for as long as needed to investigate abuse and to meet our record-keeping obligations; aggregate AI usage counters and audit entries are kept in de-identified form after an account is deleted.
3b. Where we process it
TaxNinja JP is operated from Japan, but the application servers and database currently run on Amazon Web Services in the United States (AWS region us-east-2, Ohio). Your account and tax-return data are therefore stored and processed outside Japan by AWS acting as our processor. Separately, and only if you enable the AI features, protected text is transmitted to an AI provider in the United States as described in section 4. We will update this section before changing hosting regions.
4. Third parties
We do not share personal information with third parties except where required by law or by a clearly labeled integration you opt into. When you enable the AI assistant or return review, Kemuri-protected chat text and review snapshots are sent to the configured AI provider in the United States (Anthropic, OpenAI, or xAI / Grok). We do not collect or transmit My Number digits (consent flags only). This is a foreign third-party transfer under APPI Article 28 and requires your consent before use. Changing the provider bumps the consent version and requires re-consent.
5. Your rights
You can request disclosure, correction, suspension of use, or deletion of your personal information. Use dashboard settings to export or delete your data, or contact the published support channel.
6. Security measures
Passwords are hashed with bcrypt and sessions are protected with httpOnly, SameSite=Lax cookies (Lax rather than Strict so Google sign-in redirects work), backed by Origin checks on state-changing requests. Stored credentials such as AI provider keys are encrypted at rest with AES-256-GCM. See the Security page for more detail.
7. Children
The service is intended for adults. Users under 18 should only use it with a guardian.
8. Changes
We will announce material changes at least 30 days before they take effect, in-app or by email.
Data protection officer: Contact details pending publication by the site administrator.
Important: This site is NOT tax advice. It is a tool to help you prepare your own filing.