Privacy Policy

Last updated: April 3, 2026

1. Introduction

Isshin Technology Limited ("we", "us") respects your privacy and is committed to protecting your personal information. This Privacy Policy explains what information we collect, how we use it, and the steps we take to protect it when you use Tadashii Kotoba (正しい言葉).

2. Information We Collect

We collect the following types of information:

Account Information

When you register via Google OAuth, we receive your name, email address, and profile picture from Google. When you register via magic link, we only collect your email address.

Usage Data

We record usage data such as character count usage (daily/monthly) and subscription status to manage service limits.

IP Address (Guest Users)

For unauthenticated guests, we store a hashed version of your IP address solely for rate limiting purposes. Raw IP addresses are not retained and are not linked to personal identity.

Input Text

Text you submit is sent to a third-party AI provider for processing, depending on the quality tier used. We do not store your input text permanently on our servers. Please refer to each provider's privacy policy for how they handle data sent to their AI services.

3. How We Use Your Information

  • •Providing, maintaining, and improving the service
  • •Authenticating and managing your account
  • •Processing subscriptions and payments
  • •Managing usage limits
  • •Sending important service communications (including magic link emails)
  • •Preventing fraud and ensuring security

4. Information Sharing

We do not sell or share your personal information with third parties, except in the following cases:

Service Providers

We share necessary information with: AI processing providers (which vary by quality tier), Google (OAuth authentication), Stripe (payment processing), Resend (email delivery), and Vercel (hosting and database). These providers are bound by their own privacy policies.

Legal Requirements

We may disclose information if required by law or if we believe disclosure is necessary to protect our rights, your safety, or the safety of others.

5. Data Storage & Security

Your data is stored in Vercel Postgres (a PostgreSQL database powered by Neon). Authentication uses JWTs stored in your browser's localStorage. We implement industry-standard security measures, but no method of transmission over the internet is 100% secure.

6. Cookies & Local Storage

We do not use cookies. Your authentication token (JWT) and UI language preference are stored in your browser's localStorage. This data is not transmitted to our servers independently and can be cleared by clearing your browser data.

7. Your Rights

You have the right to:

  • •Request access to the personal data we hold about you
  • •Request correction of inaccurate information
  • •Request deletion of your account and associated data
  • •Opt out of marketing communications

To exercise any of these rights, please contact us using the information below.

8. Children's Privacy

Our service is not directed at children under 13. We do not knowingly collect personal information from children under 13.

9. Changes to This Policy

We may update this Privacy Policy from time to time. For material changes, we will notify you by email. Continued use of the service after changes take effect constitutes acceptance of the updated Policy.

10. Contact Us

For questions or requests regarding your privacy, please contact us at:

Isshin Technology Limited
Hong Kong
admin@isshin.tech