End-User License Agreement

Last Updated: December 16, 2025

Please read this End-User License Agreement ("Agreement") carefully before using the iStackz mobile application ("App"). This Agreement is a legal contract between you ("User" or "you") and Christoph Lüdi ("we," "us," or "our").

By downloading, installing, or using the App, you agree to be bound by the terms of this Agreement. If you do not agree to these terms, do not download, install, or use the App.

1. License Grant

Subject to your compliance with this Agreement, we grant you a limited, non-exclusive, non-transferable, revocable license to download, install, and use the App on iOS devices that you own or control, solely for your personal, non-commercial use.

2. Restrictions

You agree not to:

• Modify, reverse engineer, decompile, or disassemble the App
• Remove, alter, or obscure any proprietary notices on the App
• Use the App for any commercial purpose or for the benefit of any third party
• Copy, distribute, or share the App except as expressly permitted by this Agreement
• Use the App in any way that violates applicable laws or regulations
• Attempt to gain unauthorized access to any portion of the App or its related systems

3. User Accounts and Content

Account Creation: You may be required to create an account to access certain features. You are responsible for maintaining the confidentiality of your account credentials and for all activities that occur under your account.

User-Generated Content: The App may allow you to create custom vocabulary lists, flashcards, or other content. You retain ownership of any content you create, but you grant us a worldwide, non-exclusive, royalty-free license to use, reproduce, and display such content solely for the purpose of operating and improving the App.

Content Standards: You agree not to upload, share, or create content that is illegal, harmful, threatening, abusive, harassing, defamatory, vulgar, obscene, or otherwise objectionable.

4. Subscription and Payments

Free and Premium Features: The App may offer both free and premium features. Premium features require a paid subscription.

Subscription Terms: Subscriptions automatically renew unless cancelled at least 24 hours before the end of the current period. Your iTunes account will be charged for renewal within 24 hours prior to the end of the current period at the rate of your selected plan.

Managing Subscriptions: You can manage your subscription and turn off auto-renewal in your iTunes Account Settings after purchase. Cancellation of the current active subscription period is not allowed.

Refunds: Refunds are handled according to Apple's App Store refund policies. No refunds will be provided for any unused portion of a subscription term.

5. Privacy and Data Collection

We collect and process your personal information in accordance with our Privacy Policy, which is incorporated into this Agreement by reference. By using the App, you consent to our collection and use of your data as described in the Privacy Policy.

The App may collect data including but not limited to your learning progress, vocabulary lists, study habits, and device information to provide and improve our services.

6. Third-Party Services

The App may contain links to third-party websites or services that are not owned or controlled by us. We are not responsible for the content, privacy policies, or practices of any third-party services. The App may integrate with Apple services including iCloud for data syncing.

7. Intellectual Property

All intellectual property rights in the App, including but not limited to the software, design, text, graphics, vocabulary content, and audio materials, are owned by us or our licensors. The vocabulary content, lessons, and educational materials provided through the App are protected by copyright and other intellectual property laws.

8. Disclaimers and Limitation of Liability

"AS IS" Basis: The App is provided "as is" and "as available" without warranties of any kind, either express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, or non-infringement.

Educational Tool: The App is designed as a vocabulary learning tool but does not guarantee any specific learning outcomes or results. Your learning success depends on various factors beyond our control.

Limitation of Liability: To the maximum extent permitted by law, we shall not be liable for any indirect, incidental, special, consequential, or punitive damages, or any loss of profits or revenues, whether incurred directly or indirectly, or any loss of data, use, goodwill, or other intangible losses resulting from your use of the App.

9. Updates and Modifications

We may update the App from time to time to add new features, fix bugs, or improve performance. These updates may be required to continue using the App. We reserve the right to modify or discontinue the App or any features at any time without notice.

We may revise this Agreement at any time by posting an updated version in the App. Your continued use of the App after such changes constitutes your acceptance of the new terms.

10. Termination

We may terminate or suspend your access to the App immediately, without prior notice, for any reason, including if you breach this Agreement. Upon termination, your right to use the App will immediately cease. Sections of this Agreement that by their nature should survive termination shall survive, including ownership provisions, warranty disclaimers, and limitations of liability.

11. Apple-Specific Terms

As required by Apple's App Store terms, you acknowledge that:

• This Agreement is between you and Christoph Lüdi, not Apple, and Apple is not responsible for the App or its content
• Apple has no obligation to provide 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 for a refund of the purchase price, and Apple will have no other warranty obligation with respect to the App
• Apple is not responsible for addressing any claims by you or any third party relating to the App or your possession and use of the App
• Apple is a third-party beneficiary of this Agreement and may enforce this Agreement against you

12. Governing Law

This Agreement shall be governed by and construed in accordance with the laws of Switzerland, specifically the Canton of Bern. Any disputes arising from this Agreement shall be resolved in the competent courts of the Canton of Bern, Switzerland. However, if you are a consumer residing in the European Union, you retain the protection afforded by mandatory provisions of consumer protection law in your country of residence.

13. General Provisions

Entire Agreement: This Agreement, along with our Privacy Policy, constitutes the entire agreement between you and us regarding the App and supersedes all prior agreements.

Severability: If any provision of this Agreement is found to be unenforceable, the remaining provisions will continue in full force and effect.

Waiver: Our failure to enforce any right or provision of this Agreement will not be considered a waiver of those rights.

14. Contact Information

If you have any questions about this Agreement, please contact us at:

Christoph Lüdi
info@stackz.com            
Mühlegasse 10, 4538 Oberbipp, Switzerland
www.stacz.com

By using the App, you acknowledge that you have read, understood, and agree to be bound by this End-User License Agreement.