Terms of Service

1. Using Keystone Languages

Keystone Languages provides grammar-first language-learning tools, including lesson pages, example sentences, audio, structured practice, spaced repetition review, and related course content. You may use the Services only if you can form a binding agreement under applicable law and comply with these Terms.

If you do not agree to these Terms, do not use the Services.

2. Eligibility and accounts

• You must be at least 13 years old, or the minimum age required in your jurisdiction, to use the Services on your own.
• You are responsible for maintaining the confidentiality of your account credentials and for activity that occurs under your account.
• You must provide accurate information when creating an account or using Google sign-in.
• You may not impersonate another person or create an account for unlawful or abusive purposes.

3. License and permitted use

Subject to these Terms, Keystone Languages grants you a limited, non-exclusive, non-transferable, revocable license to access and use the Services for your personal, non-commercial learning use.

• You may not resell, sublicense, or commercially exploit the Services or their content.
• You may not copy, scrape, reproduce, distribute, or build a competing product from the Services, except as expressly permitted by law.
• You may not reverse engineer, interfere with, or attempt to bypass security or access controls.

4. Educational content and feature limitations

The Services are designed for educational use. While we work to keep lessons, examples, audio, and exercises useful and accurate, language content can contain mistakes, omissions, or changing conventions.

• The Services are not a guarantee of exam results, fluency, or certification outcomes.
• Optional AI-assisted features and automated audio features may occasionally produce imperfect output.
• You should use your own judgment before relying on content for exams, work, travel, or other important situations.

5. Acceptable use

You agree not to misuse the Services. This includes, without limitation:

• using the Services for unlawful, infringing, harassing, fraudulent, or abusive conduct;
• probing, scanning, or testing vulnerabilities without permission;
• using bots or automation in a way that harms performance or bypasses intended product limits;
• uploading or submitting content that you do not have the right to use;
• submitting sensitive personal information into optional free-form AI features; or
• interfering with another user's use of the Services.

6. Keystone Access, billing, renewals, and refunds

Some features require a paid subscription or purchase. Keystone's current premium tier is called Keystone Access.

• For purchases made directly from Keystone Languages on the web, you may request a refund within 14 calendar days of the original purchase by emailing hello@keystonelanguages.com.
• If you purchase through Paddle on the web, billing, renewals, cancellations, payment method updates, and customer portal access are handled through Paddle under its own terms and policies.
• If you purchase through Apple App Store or Google Play, billing, renewals, cancellations, and refunds are handled by that store under its own terms and policies.
• Web subscriptions and store subscriptions may renew automatically unless canceled before the renewal date through the relevant billing portal or store account settings.
• Access to paid features may depend on successful billing, store account status, and entitlement sync.
• Prices may change in the future. Direct web billing is provided through Paddle, and any additional checkout terms are shown at the time of purchase.

7. Third-party services and app stores

Parts of the Services depend on third-party providers, including Google sign-in, Google Cloud Text-to-Speech, OpenAI, RevenueCat, Paddle, Apple App Store, and Google Play. Your use of those features may also be subject to those providers' terms and privacy practices.

Apple and Google are not responsible for providing the Keystone Languages Services themselves. Questions about the Services should be directed to Keystone Languages, not to the platform store, except for store-managed billing and refunds.

8. Intellectual property

The Services, including software, branding, course structure, lesson content, example collections, interface design, and related materials, are owned by Keystone Languages or its licensors and are protected by intellectual property laws.

These Terms do not give you ownership of the Services or any Keystone Languages intellectual property. You may not use our names, logos, or content except as expressly permitted by these Terms or by law.

9. Feedback and submitted material

If you send feedback, suggestions, or product ideas to Keystone Languages, you grant us a non-exclusive, worldwide, royalty-free right to use that feedback to improve the Services without any obligation to you.

10. Service changes, availability, and termination

We may update, modify, suspend, or discontinue parts of the Services at any time, including courses, examples, audio, pricing, feature availability, and integrations.

• We may suspend or terminate access if you violate these Terms or if needed to protect the Services, users, or the public.
• You may stop using the Services at any time and may delete your account through the app or by contacting us.
• Deleting your account may remove your progress, vocabulary deck, bookmarks, settings, and access to paid features associated with that account.

11. Disclaimers

To the maximum extent permitted by law, the Services are provided "as is" and "as available." Keystone Languages disclaims warranties of merchantability, fitness for a particular purpose, non-infringement, and uninterrupted availability, except where such disclaimers are not allowed by law.

12. Limitation of liability

To the maximum extent permitted by law, Keystone Languages and its affiliates, licensors, and service providers will not be liable for indirect, incidental, special, consequential, exemplary, or punitive damages, or for loss of profits, data, goodwill, or use, arising out of or related to the Services.

Where permitted by law, our total liability for claims relating to the Services will not exceed the amount you paid to Keystone Languages for the Services in the twelve months before the event giving rise to the claim. Nothing in these Terms limits rights that cannot be waived under applicable consumer law.

13. Changes to these Terms

We may update these Terms from time to time. If we make material changes, we will update the date above and provide notice where reasonably appropriate, such as inside the app or on the website. Your continued use of the Services after the updated Terms become effective means you accept the revised Terms.

14. Contact us

If you have questions about these Terms, support requests, or legal notices, contact Keystone Languages at hello@keystonelanguages.com.