Terms of Service

Last revised: August 16, 2026

These Terms of Service (these "Terms") set out the conditions for using the symptom-tracking app "Seren" (the "Service"), provided by Daiki Yamaguchi ("we," "us," or "our"). By using the Service, you agree to these Terms.

Before you begin, here are three things we especially want you to know (see the referenced articles for details):

• The Service is not a medical device and does not diagnose or treat any condition. Always consult a physician about your symptoms and treatment (Article 5).
• AI responses may be inaccurate. AI output is reference information only and is not medical advice (Article 6).
• In an emergency, contact emergency services (such as 911 in the United States or 119 in Japan) or a medical provider — not the Service.

Article 1 (Application)

1. These Terms apply to all relationships between you and us concerning your use of the Service.
2. Our handling of personal information is governed by the separately published Privacy Policy.
3. The commercial disclosures for the Supporter Plan (Article 4) are set out in the separately published "Legal Disclosure (Japan)" required under the Japanese Act on Specified Commercial Transactions (both documents are published on the Service's legal documents page).

Article 2 (Eligibility)

1. The Service is available to persons 16 years of age or older. Persons under 16 may not use the Service.
2. If you are a minor, please use the Service with the consent of a parent or legal guardian.

Article 3 (Registration and Account Management)

1. You register for the Service by the method we prescribe.
2. You are responsible for managing your account (authentication credentials).
3. We are not liable for damages you incur due to inadequate management of your account or use by a third party, except where caused by our intent or negligence.

Article 4 (Fees and the Supporter Plan)

1. The Service is available free of charge.
2. We offer an optional paid plan (the "Supporter Plan") for those who wish to support the development of the Service. The benefits of the Supporter Plan are as displayed in the app at the time of purchase.
3. The Supporter Plan is a monthly auto-renewing subscription offered through the App Store. The price, subscription period, and payment method are as displayed in the app and on the App Store at the time of purchase.
4. The subscription renews automatically on the same conditions unless auto-renewal is cancelled at least 24 hours before the end of the current period. You can turn off auto-renewal and cancel the subscription in your App Store account settings.
5. Payment, refunds, and other transaction terms are governed by the terms set by Apple Inc. We cannot directly process refunds of the purchase price.

Article 5 (Medical Disclaimer)

1. The Service is not a medical device. The Service is a support tool for recording, displaying, and reviewing your own symptoms, and is not intended to diagnose, treat, or prevent any disease.
2. The Service and its AI features are not a substitute for diagnosis, treatment, or medical advice by a physician or other healthcare professional. The Service is not designed to diagnose or identify medical conditions, direct the type or dosage of any medication, advise on treatment, or make medical judgments about the severity of your symptoms.
3. Information output by the Service's AI is general information and conversational support, not a medical judgment about your individual condition. Even where the AI mentions medical specialties, treatments, or medications as general medical information, such mentions are general information only and do not constitute instructions, recommendations, or a diagnosis regarding where you should seek care or what treatment or medication you should take for your individual symptoms.
4. Always consult a physician or other qualified healthcare professional for decisions about your symptoms, whether to seek medical care, and your course of treatment. In an emergency, seek medical care immediately.

Article 6 (AI Features)

1. The Service's AI features assist in organizing your records and in conversation, based on your input. You are talking to an AI, not a human counselor.
2. AI output may be inaccurate or incomplete. Do not rely on AI output uncritically; verify important matters with reliable sources. You are responsible for how you use and rely on AI output.
3. When you use the AI features, your input is transmitted to an AI analysis service (a service provider located outside Japan). See the Privacy Policy for details.

Article 7 (Your Records)

1. Rights in the content you record in the Service (symptom records, AI conversations, notes, and the like) belong to you.
2. We handle your records only to the extent necessary to provide, maintain, and improve the Service. Details are set out in the Privacy Policy.

Article 8 (Prohibited Conduct)

In using the Service, you must not:

1. violate laws, regulations, or public order and morals;
2. impersonate another person or improperly register another person's information;
3. interfere with the operation of the Service, gain unauthorized access, or reverse engineer or otherwise improperly analyze or modify the Service;
4. use the Service for medical practice or any other purpose other than its intended purpose; or
5. engage in any other conduct that we reasonably determine to be inappropriate.

Article 9 (Suspension, Modification, and Termination of the Service)

1. We may suspend or interrupt all or part of the Service without prior notice where necessary for system maintenance, or due to failures, natural disasters, or other unavoidable circumstances.
2. We may modify the content of the Service or terminate its provision. If we terminate the Service, we will endeavor to give advance notice within a reasonable period.
3. We are not liable for damages you incur as a result of suspension, modification, or termination under this Article, except where caused by our intent or negligence.

Article 10 (Withdrawal and Account Deletion)

1. You may delete your account and withdraw from the Service at any time from the app's settings screen.
2. When you delete your account, your record data held by us is deleted promptly. Deleted data cannot be restored.
3. Deleting your account does not automatically cancel your Supporter Plan subscription. To stop being charged, you must cancel the subscription yourself in the App Store subscription management screen.

Article 11 (Disclaimer of Warranties)

1. WE DO NOT WARRANT THAT THE SERVICE WILL FIT YOUR PARTICULAR PURPOSE, THAT IT WILL HAVE THE FUNCTIONS, ACCURACY, COMPLETENESS, OR USEFULNESS YOU EXPECT, OR THAT IT WILL BE UNINTERRUPTED OR ERROR-FREE. THE SERVICE IS PROVIDED "AS IS" AND "AS AVAILABLE."
2. The preceding paragraph is not intended to exempt us from any liability we bear under the Consumer Contract Act of Japan or other applicable laws that cannot be excluded by contract.

Article 12 (Limitation of Liability)

1. If you incur damages for reasons attributable to us, we are liable for compensation within the scope set out in this Article.
2. Where the damage is caused by our intent or gross negligence, we will compensate the full amount of the damage you incur.
3. WHERE YOU INCUR DAMAGES DUE TO OUR ORDINARY NEGLIGENCE (WHETHER IN CONTRACT OR IN TORT), OUR LIABILITY IS LIMITED TO DIRECT AND ORDINARY DAMAGES ACTUALLY INCURRED, AND IS CAPPED AT THE AMOUNT YOU PAID TO US AS CONSIDERATION FOR THE SUPPORTER PLAN DURING THE 12 MONTHS PRECEDING THE EVENT GIVING RISE TO THE DAMAGE (OR 1,000 JAPANESE YEN IF YOU HAVE MADE NO SUCH PAYMENT).
4. The cap in the preceding paragraph does not apply to damages involving death or personal injury.

Article 13 (Changes to these Terms)

1. We may change these Terms where we deem it necessary, in accordance with the Civil Code of Japan.
2. If we make material changes, we will announce the changes on the Service and, where necessary, ask for your renewed consent. If you continue to use the Service after a change, you are deemed to have agreed to the changed Terms.

Article 14 (Notices)

Notices and communications from us to you concerning the Service are made by display within the Service or by other methods we prescribe. For inquiries, please use the contact listed in the Privacy Policy and the Legal Disclosure (Japan).

Article 15 (No Assignment)

You may not assign or pledge your position or your rights and obligations under these Terms to any third party without our prior consent.

Article 16 (Language)

The Japanese version of these Terms is the original and controlling version. This English version is a translation provided for reference, intended to convey the same content as the Japanese version. If there is any discrepancy between the Japanese version and any translation, the Japanese version prevails.

Article 17 (Governing Law and Jurisdiction)

1. These Terms are governed by the laws of Japan. However, this does not deprive you of the protection of mandatory consumer-protection rules of the law of the place where you reside that cannot be excluded by contract.
2. Any dispute concerning the Service is subject to the exclusive jurisdiction of the court having jurisdiction over our place of business.