Privacy Policy

Last updated: March 2026

1. Data Controller

ToneShift AI is operated by Masataka Ushijima, located in Japan.

Contact: masataka.ushijima@gmail.com

2. Information We Collect

Account information — Email address, name, and profile picture provided during sign-up (via email/password).
Transformation text — The text you submit for style transformation and the resulting output.
Custom voice data — Sample text you provide to train custom voice styles (Creator and Pro plans).
Payment information — Billing details processed securely by Stripe. We do not store your credit card numbers.
Usage data — Transformation counts, feature usage, and anonymized analytics data collected by Vercel Analytics.

3. Purpose of Use and Legal Basis

To provide the service (contract performance) — Processing your text transformations, managing your account and subscription.
To process payments (contract performance) — Handling subscription billing through Stripe.
To improve the service (legitimate interest) — Analyzing anonymized usage patterns to improve features and performance.
To communicate with you (legitimate interest) — Sending service-related notifications, responding to inquiries.
To ensure security (legitimate interest) — Detecting and preventing fraud, abuse, or security incidents.

4. Third-Party Services

We use the following third-party services to operate ToneShift AI:

Supabase (authentication and database) — Privacy Policy
Stripe (payment processing) — Privacy Policy
Anthropic (AI text processing via Claude API) — Privacy Policy
Your text is processed via Anthropic's API and is not used to train their AI models, in accordance with Anthropic's API usage policy.
Vercel (hosting and analytics) — Privacy Policy

5. Cookies and Tracking

Authentication cookies — Essential cookies to maintain your login session.
Guest demo cookies — Used to track free transformation usage for non-authenticated users (limited to 3 per day).
Vercel Analytics — Privacy-friendly, anonymized web analytics. No personally identifiable information is collected.

We do not use third-party tracking cookies for advertising.

6. Data Retention

Account data — Retained until you delete your account.
Transformation history — Retained until you delete individual entries or your account.
Custom voice data — Retained until you delete the voice or your account.
Payment records — Retained for as long as necessary to fulfill legal, tax, and regulatory obligations (typically up to 7 years under Japanese tax law) and to handle billing disputes.

7. International Data Transfers

Your data may be transferred to and processed in the United States, where our third-party service providers (Supabase, Stripe, Anthropic, Vercel) operate. By using ToneShift AI, you consent to these transfers. These transfers are protected by our service providers' compliance with applicable data protection frameworks, including Standard Contractual Clauses (SCCs) and/or the EU-U.S. Data Privacy Framework where applicable. For details, please refer to each provider's privacy policy linked in Section 4.

8. Your Rights

Under applicable data protection laws (including GDPR), you have the following rights:

Access — Request a copy of the personal data we hold about you.
Rectification — Request correction of inaccurate or incomplete data.
Erasure — Request deletion of your personal data.
Data portability — Request a machine-readable copy of your data.
Restriction — Request restriction of processing of your data.
Objection — Object to processing based on legitimate interests.
Complaint — Lodge a complaint with a supervisory authority in your jurisdiction.

9. How to Exercise Your Rights

To exercise any of the above rights, please contact us at masataka.ushijima@gmail.com. We will respond to your request within 30 days.

10. Children's Privacy

ToneShift AI is not intended for use by children under 13 years of age. We do not knowingly collect personal data from children under 13. If we become aware that we have collected such data, we will take steps to delete it promptly.

11. Chrome Extension

The ToneShift Chrome extension allows you to transform selected text on any web page. When you use the extension:

Only the text you explicitly select for transformation is sent to our servers.
Your text is processed by Anthropic's Claude API for AI transformation and stored in Supabase as part of your transformation history.
We do not collect or store your browsing history, page content, or any data beyond the selected text.
All communication is encrypted via HTTPS.

12. Changes to This Policy

We may update this Privacy Policy from time to time. If we make material changes, we will notify you by email or by posting a notice on the service. Your continued use of ToneShift AI after any changes constitutes your acceptance of the updated policy.

13. Contact

If you have any questions about this Privacy Policy, please contact us at masataka.ushijima@gmail.com.