Terms of Use for VietQuest

Effective date: November 12, 2026

These Terms of Use ("Terms") govern your use of the VietQuest mobile application ("the App"), developed and operated by an independent individual developer ("we", "us"). By downloading, installing, or using the App, you agree to these Terms. If you do not agree, please do not use the App.

1. Eligibility

VietQuest is not directed or marketed to children under the age of 13. Accounts and Premium subscriptions are available only to users aged 13 or older (the App checks only your birth year, so anyone born 13 calendar years ago is treated as under 13, to err on the side of caution). If you tell the App you are under 13, account creation, sign-in and purchases are turned off for you; a parent or legal guardian may still use the App's free learning content together with you.

2. License

We grant you a limited, non-exclusive, non-transferable, revocable license to use the App on devices you own or control, for your own personal, non-commercial use, subject to these Terms and, where applicable, the Usage Rules set forth in the applicable app store's terms of service (e.g. the App Store Terms of Service).

3. Subscriptions (Premium)

VietQuest offers an optional auto-renewing subscription ("Premium") that removes the limits of the free version. Free use has daily limits on practice questions and stories, one included voice, ads, and requires an internet connection. Premium adds unlimited practice and stories, all voices, offline use, Cloud Backup of your progress across devices, and no ads. Features and limits may change over time. Current plans:

• Payment is charged to your Apple ID or Google Play account at confirmation of purchase.
• Subscriptions automatically renew unless auto-renew is turned off at least 24 hours before the end of the current period.
• Your account will be charged for renewal within 24 hours prior to the end of the current period, at the price you agreed to.
• You can manage or cancel your subscription at any time in your Apple ID (App Store) or Google Play account settings — VietQuest itself cannot process cancellations or refunds directly.
• Prices may vary by region and are subject to change; you will be notified of any price change before it applies to you, in accordance with Apple's and Google's respective policies.

4. Advertising

Free-tier (non-Premium) use of the App includes ads served through Google AdMob, as described in our Privacy Policy. Ads may be personalized depending on your device and your choices (for example, the iOS tracking prompt, Google's consent form where required, or your Android advertising settings); otherwise they are non-personalized. Free-tier gems may be used, as shown in the App, to unlock extra practice or stories. Some ads are optional "rewarded" ads that you choose to watch in exchange for gems. Premium subscribers do not see ads.

5. Accounts, Weekly Leaderboard, Referrals & Feedback

You may optionally create an account (by email/password, Google sign-in, or Apple sign-in) at no cost; an account is not needed for free use, but buying Premium requires one (with a verified email address, or a Google or Apple sign-in) so that your purchase can be restored. Premium is tied to the signed-in account: signing out turns Premium off on that device until you sign in again. Signing in lets you:

• Back up your learning progress to the cloud (Premium subscribers only).
• Appear on the weekly leaderboard (signed-in learners are included automatically; you can hide yourself in Settings), which shows your correct-answer count for the current week and a display name (chosen by you, or a generic default such as “Learner 1234”, which does not contain any part of your email) to other signed-in learners. The leaderboard resets every week. You agree not to use any method to falsify, inflate, or otherwise manipulate your leaderboard score.
• Share your personal referral code with other users, or redeem a code shared with you. When a valid referral is completed (the referred user redeems your code and finishes 3 new lessons), you and the referred user each receive 50 gems, subject to eligibility criteria we may set or change at any time (for example account age, email verification, and a limit on the number of rewarded invitations per account, with additional bonus gems at certain invitation milestones). Gems are a virtual in-app item: they have no cash value, cannot be exchanged, sold or transferred, and are not a subscription or Premium access. We may withhold or revoke a reward we reasonably believe was obtained through fraud, self-referral, multiple accounts, or abuse of the program.
• Send us feedback about the App. By submitting feedback, you agree we may use your suggestions to improve VietQuest without any obligation or compensation to you. We may, at our sole discretion, reward a submission with bonus gems — this is never guaranteed and is not owed for any particular feedback.

You are responsible for keeping your account credentials confidential and for all activity under your account. You may permanently delete your account and its associated data at any time from within the App (Settings > Delete account) — see our Privacy Policy for details on what is deleted. Deleting your account does not cancel an active subscription; cancel it in your Apple ID or Google Play subscriptions.

For account security and to discourage sharing one account among many people, an account can be signed in on a maximum of 3 devices at the same time. If you sign in on a fourth device, the device that has been active least recently is signed out automatically. Signing out of a device frees up its slot.

6. Acceptable Use

You agree not to:

• Reverse-engineer, decompile, or attempt to extract the source code of the App, except where permitted by law.
• Use the App for any unlawful purpose, or to abuse, spam, or attempt to overload our backend services.
• Share your Premium account credentials for the purpose of circumventing payment.
• Choose a nickname that is offensive, abusive or impersonates someone else; we may remove or replace such a nickname. You can report another learner's nickname with the Report button on the Leaderboard screen, and we aim to act on reports within 24 hours.
• Attempt to manipulate, falsify, or exploit the leaderboard, referral program, gem balances, or any other scoring/reward mechanism.

7. Intellectual Property

All content, design, trademarks, and code within VietQuest are the property of the developer, unless otherwise noted. You may not copy, redistribute, or create derivative works from the App without prior written permission.

8. Disclaimer of Warranties

Lessons, translations, explanations, example sentences and audio are provided for learning purposes only and may contain mistakes or omissions; we do not guarantee any level of fluency or any exam result.

The App is provided "as is" and "as available," without warranties of any kind, express or implied. We do not guarantee the App will be error-free, uninterrupted, or that any pronunciation/scoring feature will be perfectly accurate — both the Tone Match feature and the Pronunciation Practice feature (which relies on your device's built-in speech recognition) are approximate learning aids, not certified language assessment tools, and their accuracy may vary by device, operating system, accent, or background noise.

9. Limitation of Liability

To the maximum extent permitted by law, we shall not be liable for any indirect, incidental, special, exemplary, punitive, or consequential damages arising from your use of, or inability to use, the App, including but not limited to loss of data, loss of virtual items (such as gems), or loss arising from any interruption of the leaderboard or referral program.

To the maximum extent permitted by law, our total aggregate liability to you for any and all claims arising out of or relating to the App or these Terms shall not exceed the greater of (a) the total amount you paid us for Premium subscriptions in the twelve (12) months immediately preceding the event giving rise to the claim, or (b) fifty US dollars (USD $50). This limitation applies regardless of the legal theory on which the claim is based (contract, tort, or otherwise) and even if we have been advised of the possibility of such damages. Nothing in this section is intended to limit liability that cannot be limited under applicable mandatory law.

10. Indemnification

To the maximum extent permitted by law, you agree to defend, indemnify, and hold harmless the developer from and against any claims, liabilities, damages, losses, and expenses (including reasonable legal fees) arising out of or in any way connected with: (a) your violation of these Terms or the Acceptable Use section above; (b) your misuse of the leaderboard, referral program, or any other feature of the App; or (c) your violation of any rights of a third party while using the App. This section does not apply to the extent a claim arises from our own violation of these Terms or applicable law.

11. Changes to, or Discontinuation of, the App

We may modify, update, suspend, or discontinue the App (or any feature of it, including the leaderboard or referral program) at any time, with or without notice. We are not liable to you or any third party for any such modification, suspension, or discontinuation.

12. Termination

We may suspend or terminate your access to the App, or remove you from the leaderboard, if you violate these Terms. You may stop using the App, delete your account (Settings > Delete account), and delete the App at any time.

13. Changes to These Terms

We may update these Terms from time to time. Material changes will be reflected by updating the "Effective date" above. Continued use of the App after changes take effect constitutes acceptance of the updated Terms.

14. Governing Law and Dispute Resolution

These Terms are governed by the laws of Vietnam, without regard to conflict-of-law principles, except where mandatory consumer protection laws of your own country/region provide otherwise.

Any dispute, controversy, or claim arising out of or relating to these Terms or the App shall be submitted to the exclusive jurisdiction of the competent courts of Vietnam, except where mandatory consumer protection laws applicable in your country of residence entitle you to bring a claim in your local courts, in which case that right is not affected by this section. Before filing a formal claim, we encourage you to first contact us at the email address in the Contact Us section below so we can attempt to resolve the issue informally.

15. Apple App Store Additional Terms

If you downloaded the App from the Apple App Store, the following additional terms apply and take precedence over any conflicting term elsewhere in these Terms, as required by Apple:

• These Terms are between you and us only, not with Apple Inc. ("Apple"), and Apple is not responsible for the App or its content.
• The license granted to you is limited to a non-transferable license to use the App on an Apple-branded product that you own or control, as permitted by the App Store's Usage Rules.
• Apple has no obligation whatsoever to provide any maintenance or support services for the App.
• In the event of any failure of the App to conform to any applicable warranty, you may notify Apple, and Apple will refund the purchase price (if any) for the App to you; to the maximum extent permitted by law, Apple has no other warranty obligation whatsoever with respect to the App, and any other claims, losses, liabilities, damages, costs, or expenses attributable to a failure to conform to a warranty are our sole responsibility.
• We, not Apple, are responsible for addressing any claims by you or any third party relating to the App, including product liability claims, claims that the App fails to conform to legal or regulatory requirements, and claims arising under consumer protection or similar legislation.
• In the event of any third-party claim that the App or your possession and use of the App infringes a third party's intellectual property rights, we, not Apple, are responsible for the investigation, defense, settlement, and discharge of any such claim.
• You represent and warrant that you are not located in a country subject to a U.S. Government embargo, or designated as a "terrorist supporting" country, and that you are not listed on any U.S. Government list of prohibited or restricted parties.
• You must comply with any applicable third-party agreement (e.g. your wireless data service agreement) when using the App.
• Apple and Apple's subsidiaries are third-party beneficiaries of these Terms, and upon your acceptance of these Terms, Apple has the right (and will be deemed to have accepted the right) to enforce these Terms against you as a third-party beneficiary.

16. Contact Us