Terms of Use

Last updated: November 9, 2026

These Terms of Use (the "Terms") set out the conditions for using Fast Writing (the "App") provided by Thunderstruck Works ("we"). By using the App, you agree to these Terms. The Japanese version prevails if the two versions differ.

1. The service

The App provides English learning centered on quick English composition. Features include automatic AI grading, model answers, conversation with an AI tutor (Premium), and English conversation with AI characters.

2. Pricing and subscriptions

• Some features are provided through Premium, a paid subscription.
• Prices and periods are shown on the purchase screen. There is no free trial.
• Payment is charged to your App Store or Google Play account.
• Subscriptions renew automatically unless auto-renew is turned off at least 24 hours before the end of the period.
• You can cancel in your store's subscription settings.
• AI character conversation is limited to 10 times per day on the free plan. On Premium, AI grading is limited to 100 times per day and AI conversation (AI tutor and AI characters combined) to 100 times per day. We may temporarily limit use for system protection, outage response, or abuse prevention.

3. AI grading and generated content

AI grading and responses are for reference, and we do not guarantee their accuracy or completeness. You are responsible for your final learning decisions. AI characters are fictional, and what they say does not represent our views.

4. Prohibited conduct

• Use that violates laws or public order and morals
• Interfering with the App's operation, unauthorized access, or reverse engineering
• Registering content that defames others, including ranking nicknames
• Circumventing rate limits or other abuse

5. User-generated content

Display information you register, such as ranking nicknames, may be shown to other users. We may remove inappropriate content without notice.

6. Disclaimer

The App is provided as is. To the extent permitted by applicable law, we are not liable for damages arising from your use of the App.

7. Changes and termination

We may change, suspend, or end the App without notice.

8. Governing law

These Terms are governed by the laws of Japan.

9. Additional terms for App Store downloads

If you obtained the App from the App Store, the following also applies.

• These Terms are between you and us, not Apple Inc. ("Apple"). We, not Apple, are responsible for the App and its content.
• Your license is a non-transferable right to use the App on Apple-branded devices you own or control, as permitted by the Apple Media Services Terms and Conditions.
• Apple has no obligation to provide maintenance or support for the App.
• If the App fails to conform to an applicable warranty, you may notify Apple, and Apple will refund the purchase price, if any. To the extent permitted by law, any other warranty responsibility is ours.
• We, not Apple, are responsible for addressing claims relating to the App, including product liability, legal or regulatory non-compliance, and consumer protection claims.
• We, not Apple, are responsible for handling any claim that the App infringes a third party's intellectual property rights.
• You represent that you are not located in a country subject to a U.S. Government embargo and are not on any U.S. Government list of prohibited or restricted parties.
• You must comply with applicable third-party terms when using the App.
• Apple and its subsidiaries are third-party beneficiaries of these Terms, and once you accept them, Apple may enforce them against you.

10. Contact

Operator: Thunderstruck Works

Email: thunderstruckworks@gmail.com