Terms of Use

Last updated: October 6, 2026

These Terms of Use (the "Terms") are an agreement between you and Dzianis Maliush, an individual developer ("we", "us", "our"), who provides DuoFit, the iPhone and Android app that helps two people lose weight together (the "app" or "DuoFit"). You can reach us at support@duofit.site.

By creating an account or otherwise using DuoFit, you agree to these Terms. Our Privacy Policy explains how we handle your personal information. If you do not agree to these Terms, do not use DuoFit.

This English version is the official version of these Terms. If we provide a translation and it differs from this text, the English version prevails, unless mandatory law where you live requires otherwise. If you are a consumer, the law where you live may give you rights that cannot be waived by contract. Nothing in these Terms limits those rights.

1. About DuoFit

DuoFit helps two people, a couple or two friends, lose weight together. Each of you checks in every day with your weight, water, food ("on track", "so-so" or "off track"), workout and steps. Together you keep one shared streak, which grows on the days you both check in, can set a shared weight-loss goal, follow each other's progress and, if you both want to, agree on stakes: small favors for a skipped day. DuoFit needs an internet connection, and most of it only works once you have paired with a partner.

2. Who can use DuoFit

You must be at least 16 years old to use DuoFit, or older if the law where you live sets a higher age for consenting to the processing of your personal data. If you are under the age of majority where you live, you may buy a subscription only with the permission of a parent or guardian. You must not use DuoFit if the law prohibits you from doing so.

3. Your account

You sign in with Apple, with Google, or with a sign-in link sent to your email address. Give accurate information and keep access to your device and sign-in method secure.
An account is for one person, and each person should have only one account. Do not create accounts to get another free week.
You are responsible for what happens in your account. Tell us at once if you think someone else is using it.

You pair with one other person by sending them your invite link or 6-character code. You can be in only one couple at a time, and a couple has two people.
When you pair, your partner can see your name, your weight, your check-ins and steps, your progress, your streak and your stakes, and you can see theirs. Section 3 of the Privacy Policy lists exactly what your partner sees. Pair only with someone you trust, and do not post your invite code publicly.
Respect your partner's privacy. Do not share their information outside DuoFit without their permission.
Either of you can leave the couple at any time in Settings → Leave couple. When a couple ends, the shared streak, the shared goal and all stakes are cleared, and any favor still owed is cancelled. Each of you keeps your own check-in history.
You are responsible for how you treat your partner, and we are not responsible for the conduct of any user.

5. Stakes

Stakes are optional. Each partner can propose a favor that the other will do for them if the other skips a day: one of our ready-made options, such as "Cook dinner", or their own text of up to 40 characters.
A stake counts only after the other partner agrees to it. A new stake starts on the day after it is agreed. The partner who agreed can opt out at any time, and the partner who proposed it can remove it at any time. Days that have not been counted yet then no longer count.
If a stake is on and, on a given day, your partner checks in but you don't, you owe your partner the favor once that day is over for both of you. You can owe at most one favor at a time, and no favor becomes owed for a day when your couple did not have access to DuoFit. Only the partner who is owed the favor can mark it as done or let it go. A favor already owed stays until they do, unless the couple ends.
Stakes are favors only. They never involve money, payments, prizes or anything else of monetary value, and you must not use them to ask for or offer any of these. A stake must not ask for anything unsafe, illegal, sexual, humiliating or harmful to health, such as extreme dieting or exercise.
Stakes are a friendly agreement between partners, not a legal contract. They create no legal obligation. We do not enforce stakes, check whether favors are done, or settle disagreements about them.
Your own stake text is checked automatically: links, email addresses, phone numbers, money amounts, currency symbols and offensive words are not accepted. The automatic check is not perfect. If you see a stake that is inappropriate, use "Report this stake" (see Section 6).

6. Acceptable use and objectionable content

We have no tolerance for objectionable content or abusive users. You agree not to:

write stake text or any other content that is offensive, hateful, harassing, threatening, sexually explicit, discriminatory or defamatory, or that promotes self-harm, eating disorders, violence or illegal activity;
use stakes to ask for or offer money or anything of monetary value, or to share links or contact details;
use DuoFit to bully, pressure or control another person, or pair with someone without their agreement, for example by using their phone;
impersonate anyone, or create accounts with false information or to get another free week;
access other people's accounts or data, probe or test our systems for vulnerabilities, or disrupt DuoFit, including through automated access, scraping or excessive requests;
copy, modify, reverse engineer, decompile or create derivative works of the app, except where the law allows it;
use DuoFit for any unlawful purpose or in a way that breaks these Terms or the rules of the app store you got it from.

Reporting. To report a stake, tap "Report this stake" next to it. This opens an email to us with the stake's ID and text. You can report anything else by writing to support@duofit.site. We review reports promptly, aiming to act within 24 hours. We may remove content, end stakes, and suspend or close the accounts of people who break these rules.

Protecting yourself. You can decline or opt out of any stake at any time, and you can leave the couple at any time, which ends all contact with that person through DuoFit.

7. Free week and subscriptions

7.1 Free week

Each person gets one free week (7 days) of full access to DuoFit. It starts when you create your first couple. If you first join someone else's couple instead, your free week ends at the same time as theirs. A couple has free access until the earlier of the two partners' free weeks ends.
The free week is our own offer, not an offer from the App Store or Google Play. You don't enter any payment details, and nothing is charged automatically when it ends. If notifications are on, we remind you the day before it ends.
You get the free week only once. Leaving a couple, creating a new couple, joining another couple, or deleting your account and signing up again with the same Apple ID, Google account or email address does not give you another one.
When free access ends and neither partner has a subscription, Home, check-ins, progress, the shared goal and stakes are locked for both of you until one of you subscribes. You can still edit your profile, manage your couple, restore purchases, sign out and delete your account.

7.2 DuoFit Premium

DuoFit Premium is an auto-renewable subscription, offered monthly or yearly. The price, including any taxes the store charges, is shown in the app and in the store before you buy. Prices may differ by country.
One subscription covers both of you. While you are in a couple, a subscription held by either partner gives both partners access. If the couple ends, the subscription stays with the person who bought it, and the other person loses the access it provided.
If both of you subscribe, each of you is billed separately. One subscription is enough, so one of you can cancel.
A subscription belongs to the App Store or Google Play account that bought it and gives access to one DuoFit account at a time. If you restore it in another DuoFit account, access moves to that account. Subscriptions are not shared through Family Sharing.

7.3 Billing and automatic renewal

App Store. Payment is charged to your Apple Account when you confirm the purchase. Your subscription renews automatically for the same period at the then-current price unless you cancel it at least 24 hours before the end of the current period. Your account is charged for the renewal within 24 hours before the end of the current period. You can manage and cancel your subscription in your Apple Account settings after purchase (apps.apple.com/account/subscriptions).

Google Play. Payment is charged to your Google Play account when you confirm the purchase. Your subscription renews automatically for the same period at the then-current price until you cancel it. You can manage and cancel it in Google Play → Payments & subscriptions → Subscriptions (play.google.com/store/account/subscriptions).

Deleting the app or your DuoFit account does not cancel your subscription.

7.4 Cancellation and refunds

When you cancel, your subscription stays active until the end of the period you have paid for and then does not renew. Payments are handled by Apple or Google, so refunds are handled by them under their own policies: for App Store purchases, request a refund at reportaproblem.apple.com; for Google Play purchases, use Google Play. We cannot issue refunds for App Store purchases ourselves. Your statutory rights as a consumer, including any right of withdrawal, are not affected.

7.5 Price changes

We may change subscription prices. The App Store or Google Play will tell you in advance and, where required, ask for your consent. A new price applies from your next renewal. If you don't want to pay it, cancel before the renewal.

7.6 Restoring purchases

If you reinstall DuoFit or change devices, use Settings → Restore purchases while signed in to the store account you paid with.

8. Health and safety

DuoFit is a wellness app, not a medical device. It does not give medical advice and does not diagnose, treat, cure or prevent any disease or condition. Nothing in DuoFit replaces advice from a doctor or other qualified health professional.
Talk to your doctor before you start a weight-loss program, especially if you are pregnant or breastfeeding, are under 18, have a medical condition, take medication, or have or have had an eating disorder. If you have or have had an eating disorder, DuoFit may not be right for you.
Limits in the app. DuoFit does not let you set a target weight below a body mass index (BMI) of 18.5 for your height, and suggests losing no more than about 1 kg (2 lb) a week. These are general limits, not personal advice, and BMI does not suit everyone.
Listen to your body. Stop and seek medical help if you feel unwell. In an emergency, call your local emergency number.
Accuracy. Step counts from Apple Health or Health Connect, and the values you enter, may be inaccurate. We do not check them.
Motivation, not pressure. Streaks and stakes are meant to motivate you. Don't let them push you into unsafe eating or exercise; you can opt out of any stake at any time.

9. Your content

You keep ownership of the content you add to DuoFit, such as your profile, check-ins and stake text. You give us a non-exclusive, worldwide, royalty-free license to store, process and display that content only to operate DuoFit, including showing it to your partner, for as long as your account exists and, after that, only as described in the Privacy Policy. You are responsible for your content and confirm that it is accurate and lawful. We may remove content that breaks these Terms.

10. Third-party services

DuoFit works with services run by other companies, such as the Apple App Store, Google Play, Sign in with Apple, Google Sign-In, Apple Health and Health Connect. Their own terms and privacy policies apply when you use them. We are not responsible for those services, and their availability may change.

11. License and intellectual property

License. We give you a personal, limited, non-exclusive, non-transferable, revocable license to download and use DuoFit for your own non-commercial use on devices you own or control, in line with these Terms and the rules of the store you got it from.
Ownership. DuoFit, including its software, design, logo, name, texts and graphics, belongs to us or our licensors and is protected by law. These Terms give you no rights in DuoFit other than the license above.
Feedback. If you send us ideas or suggestions, we may use them without any obligation to you.

12. Changes to DuoFit and availability

We may change, add or remove features, and we may suspend or stop offering DuoFit. We will try to tell you in advance about significant changes and, if we stop offering DuoFit, give you reasonable notice where possible. We do not promise that DuoFit will always be available or free of errors: it may be interrupted for maintenance, by technical problems, or when services it depends on are unavailable.

13. Disclaimers

To the extent the law allows, DuoFit is provided "as is" and "as available", without warranties of any kind, whether express or implied, including warranties of merchantability, fitness for a particular purpose, accuracy and non-infringement. We do not promise any weight-loss result. If you are a consumer, this section does not affect your statutory rights.

14. Limitation of liability

To the extent the law allows:

we are not liable for indirect, incidental, special, consequential or punitive damages, or for loss of data, profits or goodwill;
we are not liable for the conduct of your partner or any other user, for stakes, or for health decisions you make;
our total liability for all claims relating to DuoFit is limited to the amount you paid for DuoFit in the 12 months before the claim arose.

Nothing in these Terms limits or excludes liability for death or personal injury caused by our negligence, for fraud, or any other liability that cannot be limited or excluded under applicable law.

15. Suspension and termination

You can stop using DuoFit at any time and delete your account in the app in Settings → Delete account. Deleting your account does not cancel a subscription (Section 7.3).
We may suspend or close your account, or limit your access, if you seriously or repeatedly break these Terms, if the law requires it, or to protect your partner, other people or DuoFit. Where appropriate, we will tell you why.
When your account is deleted, your personal information is deleted as described in the Privacy Policy. The parts of these Terms that by their nature should continue to apply after they end, such as those on intellectual property, disclaimers, limitation of liability and governing law, continue to apply.

16. Changes to these Terms

We may update these Terms. We will change the "Last updated" date at the top, and if a change is significant, we will tell you in the app or by email before it takes effect. If you keep using DuoFit after a change takes effect, the updated Terms apply to you. If you don't agree with them, stop using DuoFit and delete your account.

17. Governing law and disputes

These Terms are governed by the laws of Georgia, without regard to its conflict-of-laws rules, except where the mandatory consumer protection law of the country where you live applies. Disputes will be resolved by the competent courts of Georgia, unless the law where you live gives you the right to bring proceedings in your own country. Before you go to court, please contact us first: most problems can be solved quickly.

18. App Store terms

If you got DuoFit from the Apple App Store, the following also applies:

Acknowledgement. These Terms are concluded between you and us only, not with Apple. We, not Apple, are solely responsible for DuoFit and its content.
Scope of license. The license in Section 11 lets you use DuoFit on Apple-branded products that you own or control, as permitted by the Usage Rules in the Apple Media Services Terms and Conditions.
Maintenance and support. We, not Apple, are solely responsible for providing maintenance and support for DuoFit. Apple has no obligation to provide any maintenance or support for DuoFit.
Warranty. We are solely responsible for any product warranties, whether express or implied by law, to the extent they are not effectively disclaimed. If DuoFit fails to conform to any applicable warranty, you may notify Apple, and Apple will refund the purchase price, if any, for DuoFit to you. To the maximum extent permitted by law, Apple has no other warranty obligation with respect to DuoFit, and any other claims, losses, liabilities, damages, costs or expenses attributable to a failure to conform to a warranty are our responsibility.
Product claims. We, not Apple, are responsible for addressing any claims by you or any third party relating to DuoFit or your possession or use of it, including product liability claims, any claim that DuoFit fails to conform to any applicable legal or regulatory requirement, and claims arising under consumer protection, privacy or similar legislation, including in connection with DuoFit's use of HealthKit.
Intellectual property claims. If a third party claims that DuoFit or your possession and use of it infringes that third party's intellectual property rights, we, not Apple, are solely responsible for the investigation, defense, settlement and discharge of that claim.
Legal compliance. You represent and warrant that you are not located in a country that is subject to a U.S. Government embargo or that has been designated by the U.S. Government as a "terrorist supporting" country, and that you are not listed on any U.S. Government list of prohibited or restricted parties.
Developer contact. Questions, complaints or claims about DuoFit should be sent to us using the details in Section 21.
Third-party terms. You must comply with any applicable third-party terms when using DuoFit, such as your mobile data service agreement.
Third-party beneficiary. Apple and Apple's subsidiaries are third-party beneficiaries of these Terms. Once you accept these Terms, Apple will have the right, and will be deemed to have accepted the right, to enforce these Terms against you as a third-party beneficiary.

19. Google Play

If you got DuoFit from Google Play, the Google Play Terms of Service also apply to your download and your purchases. Google is not a party to these Terms and is not responsible for DuoFit.

20. General

Entire agreement. These Terms, together with the Privacy Policy and, where they apply, the terms of the app store you got DuoFit from, are the entire agreement between you and us about DuoFit.
Severability. If any part of these Terms is found unenforceable, the rest stays in effect.
No waiver. If we don't enforce a part of these Terms, that does not mean we give up the right to enforce it later.
Transfer. We may transfer these Terms to someone who takes over DuoFit. You may not transfer your rights under these Terms without our consent.
Events outside our control. We are not responsible for delays or failures caused by events outside our reasonable control.
Notices. We may send you notices in the app or by email to the address linked to your account.

21. Contact

Questions about these Terms: support@duofit.site. DuoFit is provided by Dzianis Maliush, individual developer.