These Terms of Service ("Terms") govern your use of the String AI app. By downloading, accessing, or using String AI, you agree to these Terms. If you do not agree, please do not use the app. Questions: stringaiapp@gmail.com.
1. The service
String AI is an AI-powered practice app for violin, viola, and cello. It listens to your playing and watches your posture to give automated feedback on intonation, rhythm, tone, dynamics, and posture, and it plans practice missions and drills. Coaching messages, practice plans, and weakness diagnoses in this service are produced by generative artificial intelligence (OpenAI API). The app is an educational and practice aid — not a substitute for a qualified teacher, and not a medical, physical-therapy, or health service.
2. Eligibility and minors
You must be able to form a binding contract to use String AI. Students under 14 may use the app only with the explicit consent of a parent or legal guardian, who accepts these Terms on the student's behalf. A parent or guardian who provides consent is responsible for supervising the minor's use and may review, export, or delete the minor's data at any time. We apply a 14-year threshold globally, consistent with COPPA (US) and PIPA (Korea).
3. Your account
You are responsible for keeping your account credentials secure and for activity under your account. Provide accurate information (a valid email and display name). You may delete your account at any time from Profile > Privacy & Data; deletion permanently removes your personal data within 30 days, as described in our Privacy Policy.
4. Subscriptions, billing, and auto-renewal
String AI offers optional auto-renewing monthly subscriptions. All purchases are processed by the Apple App Store or Google Play — we never handle or store your payment details.
| Plan | Daily lesson time | Price (USD) |
|---|---|---|
| Basic | 15 min/day | $14.99 / month |
| Casual | 30 min/day | $29.99 / month |
| Standard | 45 min/day | $44.99 / month |
| Pro | 60 min/day | $59.99 / month |
Prices are shown in your local currency at checkout and may vary by region and applicable tax. Each subscription renews automatically for successive one-month periods and your payment method is charged at the start of each period, until you cancel. You can cancel anytime in your Apple App Store or Google Play account settings; cancellation takes effect at the end of the current billing period, and you keep access until then. Managing and canceling subscriptions is done through the store, not through us.
5. Free trial
String AI may offer a 7-day free trial. The trial does not automatically convert into a paid subscription — when it ends, you simply choose a plan if you wish to continue, and no charge is made unless you actively subscribe.
6. Refunds
Because payments are processed by Apple and Google, refunds are governed by their policies and handled through them (Apple: reportaproblem.apple.com; Google Play: Play Store order history). We are glad to help you with subscription questions at stringaiapp@gmail.com, but we cannot directly issue store refunds.
7. AI feedback disclaimer
Feedback, scores, diagnoses, and practice plans are generated automatically and may be incomplete or incorrect. They are guidance, not professional instruction. Use your own judgment and, for serious technique or health concerns, consult a qualified teacher or medical professional. If you feel pain or discomfort while playing, stop and seek appropriate advice — the app cannot assess injury risk.
8. Acceptable use
Do not reverse-engineer, resell, or misuse the app; do not upload unlawful content; do not attempt to disrupt or gain unauthorized access to our systems. We may suspend accounts that violate these Terms or applicable law.
9. Intellectual property
The app, its software, design, and original content are owned by String AI and its licensors. We grant you a personal, non-transferable, non-exclusive license to use the app for its intended purpose. Sheet music and other third-party materials remain the property of their respective owners. Your practice data belongs to you.
10. Disclaimers and limitation of liability
The app is provided "as is" and "as available," without warranties of any kind to the fullest extent permitted by law. To the maximum extent permitted by applicable law, String AI is not liable for indirect, incidental, or consequential damages, or for any loss arising from reliance on AI feedback. Nothing in these Terms limits liability that cannot be limited by law (including certain rights of consumers and minors).
11. Changes to these Terms
We may update these Terms as the service evolves. Material changes will be posted here with a new effective date, and where required we will notify you in-app. Continued use after changes means you accept the updated Terms.
12. App Store (Apple) additional terms
If you download String AI from the Apple App Store, the following apply: (a) these Terms are between you and String AI only, not Apple, and Apple is not responsible for the app or its content; (b) Apple has no obligation to provide any maintenance or support for the app; (c) in the event the app fails to conform to any applicable warranty, you may notify Apple and Apple will refund the purchase price (if any), and to the maximum extent permitted by law Apple has no other warranty obligation; (d) Apple is not responsible for addressing any claims relating to the app, including product-liability, legal/regulatory, or intellectual-property claims; (e) you represent that you are not located in a country subject to a US Government embargo and are not on any US Government restricted-parties list; and (f) Apple and its subsidiaries are third-party beneficiaries of these Terms and may enforce them against you.
13. Termination
You may stop using String AI and delete your account at any time from Profile > Privacy & Data. We may suspend or terminate your access if you materially breach these Terms or applicable law, or where required to protect users or comply with legal obligations. On termination, your right to use the app ends; provisions that by their nature should survive (such as disclaimers, limitation of liability, intellectual property, and governing law) continue to apply. Your subscription, if any, is managed and cancelled through the Apple App Store or Google Play, not by account deletion alone.
14. Severability and entire agreement
If any provision of these Terms is found unenforceable, the remaining provisions stay in full effect. These Terms, together with our Privacy Policy, are the entire agreement between you and String AI regarding the app. Our failure to enforce any right is not a waiver of that right.
15. Governing law and contact
These Terms are governed by the laws of the Republic of Korea, without regard to conflict-of-law rules, and subject to any mandatory consumer-protection rights of your country of residence. Questions or notices: stringaiapp@gmail.com.