Terms of Service
Last updated: 8 September 2026
These terms are the agreement between you and Beijing Zhang Liang World Technology Co., Ltd. covering your use of KnowSleep (晓眠, "the app"). Downloading, installing or using the app means you accept them. If you do not, please do not use the app.
1. What the app is
The app is an iPhone tool that interprets sleep habits. With your permission it reads the sleep and related data already in Apple Health, combines it with the behaviour tags you record, and produces a morning brief, trends and habit findings — all on your device.
The app measures nothing. Measurement is done by your Apple Watch and Apple Health; the app only interprets. Its output is therefore only as good as the completeness of your watch data and the accuracy of the tags you record.
2. Licence
Subject to these terms, we grant you a personal, non-exclusive, non-transferable, non-sublicensable licence to use the app on Apple devices that you own or control. We retain ownership of the app and all intellectual property in it; nothing here transfers ownership.
3. Who may use it
You must be at least 13 years old. If you are under 18, use the app with the knowledge and consent of a parent or guardian, and any purchase should be made or approved by them.
4. Purchases and subscriptions
- The core of the app is free. Attribution findings, the full set of sleep switches, 30-day trends and share cards require a purchase.
- There are two options: a yearly subscription (¥68/year, including a 7-day free trial) and a lifetime purchase (¥98, one-time). Prices are set in Chinese yuan; the App Store shows the matching local price tier in other regions.
- The 7-day free trial does not start on the day you install. It starts once you have enough data for your first attribution to be calculated, so that you have seen a finding of your own before paying for anything.
- Subscriptions renew automatically unless auto-renewal is turned off at least 24 hours before the end of the current period. Your Apple ID is charged within 24 hours prior to the end of the period.
- Manage or cancel under Settings → Apple ID → Subscriptions on your iPhone. Deleting the app does not cancel a subscription.
- All transactions are completed by Apple and governed by Apple's terms. Refunds are handled by Apple; please use Apple's refund process. We cannot issue refunds on Apple's behalf.
- "Lifetime" means the app remains available to you for its foreseeable operating life. It is not a promise of any specific duration.
5. Your data
The app has no server. Your health data and behaviour tags exist only on your device. We cannot access them, cannot retrieve them, and cannot restore them for you. Deleting your data or the app deletes it permanently. See the Privacy Policy.
6. Findings are findings
Every attribution, trend and suggestion the app produces is a statistical observation drawn from your own history. It shows correlation, not necessarily causation. Sleep is affected by a great many things, and the app can only see the few you tell it about.
Treat these findings as leads worth trying, not as established fact.
7. Restrictions
You may not reverse engineer, decompile or attempt to derive the source code of the app (except where law expressly permits); rent, lend, resell or redistribute it; remove any proprietary notice; or use it for any unlawful purpose.
8. Disclaimer
The app does not diagnose. It is not a medical device. It is not intended to prevent, diagnose, treat or mitigate any disease, and it does not replace a doctor, a medical service, or professional medical advice.
If you have a sleep disorder, a cardiovascular condition, or any other health concern, consult a doctor. Do not delay seeking medical advice because of anything in the app, and do not change any prescribed treatment or medication on the basis of it.
The app is provided "as is". To the fullest extent permitted by law, we disclaim all warranties, express or implied, including merchantability, fitness for a particular purpose, accuracy, and uninterrupted operation.
9. Limitation of liability
To the fullest extent permitted by law, we are not liable for any indirect, incidental, special or consequential damages. In no event will our total liability relating to the app exceed the amount you actually paid for it in the preceding twelve months.
Some jurisdictions do not allow the exclusion of implied warranties or the limitation of certain liabilities; in those jurisdictions the limits above apply to the greatest extent the law allows.
10. About Apple
Apple is not a party to these terms. Apple has no responsibility for the app or its content and no obligation to provide any maintenance or support. If the app fails to conform to any applicable warranty, you may notify Apple and Apple will refund the purchase price; to the maximum extent permitted by law, Apple has no other obligation with respect to the app. Apple and its subsidiaries are third-party beneficiaries of these terms and may enforce them as such.
11. Changes to these terms
We may update these terms. The date at the top of this page changes when we do. If a change is material we will say so inside the app. Continuing to use the app after a change takes effect means you accept the updated terms.
12. Termination
You may end these terms at any time by deleting the app. We may terminate your licence if you materially breach them. Sections 5, 6, 8, 9 and 10 survive termination.
13. Governing law
These terms are governed by the laws of the People's Republic of China, excluding its conflict-of-law rules. Disputes should first be addressed through good-faith discussion; failing that, they will be submitted to the competent people's court at our place of business. Nothing here affects mandatory consumer-protection rights you have where you live.
14. Contact
- Email: [email protected]
- Operator: Beijing Zhang Liang World Technology Co., Ltd.