Terms of Service

Effective on launch · last revised 8 June 2026

Tendo is a free, complete daily Hamilton-path puzzle. These terms explain what you can expect from us, what we ask of you, and how the optional purchases work. We've kept them as plain as we reasonably can.

Tendo shows no ads, requires no account or login, and the full game is free forever. The only purchases are two optional in-app items described in Section 5.

1. Agreement

By installing, accessing, or using Tendo (the "App"), you agree to these Terms of Service ("Terms"). If you do not agree, please do not use the App.

The App is provided by KKD studios ("we", "us"). These Terms, together with our Privacy Policy, form the complete agreement between you and us.

2. Eligibility

You must be at least 13 years old to use Tendo.
If you are between 13 and the age of majority in your jurisdiction, you should have your parent's or guardian's consent.
Children under 13 are not permitted to use the App.

3. License to use Tendo

We grant you a personal, non-exclusive, non-transferable, revocable license to install and use Tendo on your devices for your own personal, non-commercial enjoyment. This license is subject to these Terms.

The free game is 100% complete. There is no paywalled difficulty, no locked daily puzzle, and no advertising. The optional purchases in Section 5 are quality-of-life conveniences, not requirements to play.

4. No account — anonymous play

Tendo does not require account creation, sign-in, or any login. You play anonymously.

The App generates a random anonymous device identifier (DeviceID), stored locally on your device (in your browser's local storage). It is not linked to your real identity and is used only to operate gameplay features such as the country leaderboard and help requests.
Your game progress is stored locally on your device.
We send your anonymous DeviceID, your country, and your solve scores to the Tendo Cloudflare Worker so leaderboards work. Purchase history is verified through the app store. Crash logs are collected via Sentry (which you can opt out of, and from which personal data is scrubbed).

See our Privacy Policy for full details.

5. In-app purchases

Tendo offers two optional in-app purchases. All purchases are handled by your app store (Apple App Store via StoreKit 2, or Google Play via Play Billing) and managed for us through RevenueCat. We never see or handle your card or payment details.

Item	Type	Price	What it does
Tendo Plus (plus_monthly)	Auto-renewing subscription	$1.99 / month	Quality-of-life features
Tendo Plus (plus_yearly, optional)	Auto-renewing subscription	$14.99 / year	The same Tendo Plus entitlement, billed yearly
Streak Shield (streak_shield)	One-time consumable	$1.99	Grants one streak shield to protect your streak

The monthly and yearly Tendo Plus options unlock the same entitlement — the only difference is the billing period.

5.1 Auto-renewal and cancellation

A Tendo Plus subscription renews automatically at the end of each billing period unless you cancel it.
Your store charges the renewal to your account within 24 hours before the current period ends, unless you cancel at least 24 hours beforehand.
You can cancel or manage your subscription at any time through your app store — in your Apple ID subscription settings (iOS) or Google Play subscription settings (Android). Cancelling stops future renewals; you keep access until the end of the period you've already paid for.
The Streak Shield is a one-time consumable: it does not renew and is used up when applied.

Refunds and billing disputes are handled by your app store under its policies. We do not process payments directly and cannot issue store refunds ourselves.

6. Acceptable use

You may use Tendo for personal, non-commercial enjoyment. You may not:

Reverse engineer, decompile, or attempt to extract source code, except where applicable law permits
Use bots, scripts, or other automated tools to solve puzzles or manipulate leaderboards
Submit fraudulent solve events
Circumvent in-app purchase verification
Use Tendo to harass, threaten, or impersonate any person
Use Tendo for any purpose that violates applicable law

If we detect abuse, we may limit your leaderboard impact, suspend, or terminate your access, at our reasonable discretion.

7. Intellectual property

7.1 Tendo's IP

The Tendo app, its content (puzzles, animations, branding, the "ink-on-paper" aesthetic, and the path-replay design), its source code, and its trademarks — including "Tendo" and "KKD studios" — are owned by us or our licensors. You may not copy, modify, distribute, sell, or lease any part of Tendo, create derivative works, or use our trademarks or branding without our written permission.

7.2 Your content

You keep ownership of anything you create using Tendo, such as your solve history and any share cards you export. When you use Tendo's sharing features, you grant us a non-exclusive, royalty-free license to display and process that shared content only to deliver the sharing feature. We do not use your shared content for marketing without your explicit consent.

7.3 The Hamilton-path concept

The Hamiltonian-path problem is a mathematical concept in the public domain. No one owns the math. Tendo's specific puzzle generation, presentation, and gameplay design are our intellectual property.

7.4 Open-source acknowledgments

Tendo uses open-source software. A complete list is available in the App under Settings → About → Open source acknowledgments, and each dependency's license is respected.

8. Country leaderboard

The country leaderboard is an aggregate, anonymous view.
Your country is determined server-side from your network connection via Cloudflare; we do not store your IP address.
Our anti-cheat checks may exclude a solve from the country aggregate (but not from your personal stats) if they detect fraudulent patterns.

9. Service availability

We aim for high availability but do not guarantee uninterrupted service.
We may modify, suspend, or discontinue Tendo or any feature, with reasonable notice for material changes.
If we permanently discontinue Tendo, we will provide advance notice.

10. Languages

Tendo is available in English, Japanese (日本語), Traditional Chinese (繁體中文), and Simplified Chinese (简体中文). These Terms are published in those languages; if there is any inconsistency between versions, the English version governs.

11. Disclaimers

The App is provided "as is" and "as available", without warranties of any kind, express or implied, including warranties of merchantability, fitness for a particular purpose, and non-infringement.

We do not warrant that the App will be uninterrupted, secure, or error-free; that defects will be corrected; that country leaderboard data is real-time (it is aggregated periodically); or that any puzzle is solvable within a specific time.

12. Limitation of liability

To the maximum extent permitted by law, KKD studios will not be liable for any indirect, incidental, special, consequential, or punitive damages, or any loss of profits, revenue, or data, whether incurred directly or indirectly.

Our total cumulative liability arising out of or relating to these Terms or the App will not exceed the greater of $20 USD or the amount you paid us in the 12 months before the event giving rise to the liability.

Some jurisdictions do not allow the exclusion of certain damages, so these limits may not apply to you.

13. Indemnification

You agree to indemnify and hold KKD studios harmless from any claims, damages, or expenses arising from your violation of these Terms, your misuse of the App, or your infringement of any third-party rights through your use of the App.

14. Termination

By you: You may stop using Tendo at any time. To remove your local data, clear it from within the App's settings or uninstall the App.
By us: We may suspend or terminate your access if you violate these Terms, with reasonable notice unless immediate action is needed to protect the service or other users.

Termination does not entitle you to a refund of unused subscription periods, except as required by law. Subscription refunds, where available, are handled by your app store.

15. Governing law and disputes

These Terms are governed by the laws of [to be finalized], without regard to conflict-of-laws principles.

If a dispute arises, we ask that you first contact us at tendo@smartrich.ai so we can try to resolve it informally — we aim to respond within 14 days. The further dispute-resolution process and any arbitration body are [to be finalized]. Nothing in this section limits any statutory consumer-protection rights you may have where you live.

16. Changes to these Terms

We may update these Terms as Tendo evolves. When we do, we will update the "last revised" date at the top of this page and, for material changes, notify you in the App. By continuing to use Tendo after a change takes effect, you accept the updated Terms. If you do not agree to a change, please stop using Tendo.

17. Miscellaneous

Severability: If any provision is found unenforceable, the rest stays in effect.
No waiver: If we don't enforce a right, that doesn't waive it.
Assignment: You may not assign these Terms; we may assign them to a successor entity.
Entire agreement: These Terms and the Privacy Policy are the entire agreement between you and us.

18. Contact

Questions about these Terms? Email us at tendo@smartrich.ai.

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