Terms of Service (English Translation — Reference Only)
This is an English reference translation of the Japanese original. In case of any discrepancy, the Japanese version prevails.
Last updated: September 10, 2026
These Terms of Service ("Terms") set forth the conditions for using the mobile application "Sentto" (the "Service") provided by Sentto Development Team ("we," "us," or "the Team"). By using the Service, you are deemed to have agreed to these Terms.
Article 1 (Application)
These Terms apply to all relationships between the Team and users regarding the use of the Service.
Article 2 (Definitions)
"Free Plan" refers to the scope of features available at no cost within the Service.
"Pro Plan" refers to the paid subscription plan offered by the Team via Apple App Store in-app purchase.
"Generated Content" refers to Japanese sentences, furigana readings, romaji transliteration, and audio data generated by AI based on Chinese text input by the user.
Article 3 (Account Registration)
Users must create an account via the methods designated by the Team (email and password registration, or "Sign in with Apple") to use the Service.
Users shall keep their registration information accurate and up to date.
Users are responsible for managing their own accounts. Except where caused by the Team's willful misconduct or gross negligence, the Team is not liable for unauthorized use by third parties.
Article 4 (Eligibility)
The Service is not intended for individuals under the age of 13. Individuals under 13 may not use the Service.
Minors using the Service (particularly the paid Pro Plan) must obtain the consent of a parent or legal guardian.
Article 5 (Free Plan and Pro Plan)
The Free Plan is subject to a daily limit on the number of AI generations (the limit is set by the Team and may be changed with prior notice).
The Pro Plan is an auto-renewing subscription priced at US$5.99/month (per the price displayed on the App Store), offered through Apple App Store in-app purchase (displayed currency and amount may vary by country/region based on App Store pricing).
The Pro Plan automatically renews unless canceled by the user, with renewal charges applied no later than 24 hours before the end of the current period.
Cancellation must be performed by the user via the Apple ID settings screen ("Subscriptions" management page). The Team's app cannot directly cancel the subscription on Apple's behalf. See Apple's official support page on how to cancel a subscription for details.
Refunds: Since payments are processed through Apple App Store, refund eligibility and procedures are governed by Apple Inc.'s policies. The Team cannot process refunds directly. To request a refund, please use Apple's designated process (reportaproblem.apple.com).
Article 6 (Fees and Payment Method)
Payment for the Service is made exclusively through Apple App Store in-app purchase. The Team does not directly collect users' credit card or other payment information. Prices follow those displayed on the App Store.
Generated Content provided by the Service (Japanese sentences, furigana, romaji, AI-generated audio, etc.) is automatically produced by an AI model, and the Team does not guarantee its grammatical accuracy, translation appropriateness, pronunciation accuracy, or any other accuracy or completeness.
Generated Content is provided solely for language-learning reference purposes and is not a substitute for official translation, interpretation, or professional judgment in legal, medical, or business contexts. For important situations (contracts, official procedures, medical matters, important business communications, etc.), please have the content verified by a professional or native speaker.
Except where caused by the Team's willful misconduct or gross negligence, the Team is not liable for any damages arising from Generated Content.
Article 8 (Prohibited Conduct)
Users shall not engage in the following when using the Service:
Acts that violate laws or public order and morals;
Acts that infringe the intellectual property, portrait, privacy, or other rights of the Team or third parties;
Using the Service's AI generation feature to produce illegal, harmful, discriminatory, obscene, or defamatory content;
Exploiting bugs or vulnerabilities in the Service, reverse engineering, or unauthorized access;
Circumventing Free Plan usage limits by fraudulently obtaining multiple accounts;
Any act that may interfere with the operation of the Service;
Any other act the Team deems inappropriate.
If the Team determines that a user has violated the above, it may suspend or delete the user's account without prior notice.
Article 9 (Intellectual Property)
Copyright and other rights to Chinese text input by the user into the Service belong to the user.
AI-Generated Content may be freely used by the user for their own language-learning purposes. However, because the possibility of Generated Content coincidentally resembling existing third-party works cannot be entirely excluded, users are responsible for verifying rights before using Generated Content for commercial or public purposes.
Intellectual property rights in the Service application itself (design, logo, mascot character, program, etc.) belong to the Team or the rightful rights holder.
Article 10 (Changes, Suspension, and Termination of the Service)
The Team may change, add to, or discontinue the content of the Service after notifying users in advance.
The Team may suspend all or part of the Service without prior notice due to system maintenance, natural disasters, communication line failures, or other unavoidable circumstances.
If the Team discontinues the Service, it will endeavor to notify users in advance to the extent possible.
Article 11 (Disclaimer and Limitation of Liability)
The Team makes no express or implied warranty that the Service will meet any particular purpose of the user, possess any expected function or value, or that the user's use of the Service will comply with laws applicable to the user.
Except where caused by the Team's willful misconduct or gross negligence, the Team is not liable for any damages arising from the Service. Where the Team is liable for damages, such liability shall be limited to the amount of subscription fees actually paid by the user for the month in which the damage occurred.
The preceding paragraph does not apply in cases of the Team's willful misconduct or gross negligence (this provision reflects the intent of Japan's Consumer Contract Act).
Article 12 (Changes to These Terms)
The Team may amend these Terms after providing prior notice to users, where deemed necessary. Amended Terms take effect once announced in the manner designated by the Team.
Article 13 (Governing Law and Jurisdiction)
These Terms shall be governed by the laws of Japan.
Any dispute arising in connection with the Service between the Team and a user shall be subject to the exclusive agreed jurisdiction of the Tokyo District Court as the court of first instance.
Article 14 (Contact)
For inquiries regarding these Terms, please contact: