Privacy Policy

1. Who we are and what this policy covers

Keystone Languages provides grammar-first language-learning products that help learners understand language patterns through explanations, example sentences, audio, and structured practice. This Privacy Policy applies to personal information processed through our apps, web app, website, and customer support communications.

This policy does not control the privacy practices of Apple, Google, payment platforms, or other third parties that operate their own services. Those providers have their own privacy notices, and you should review them separately.

2. Information we collect

• Account and sign-in data. If you create an account, we collect information such as your email address, display name, password hash, and timestamps related to account creation and acceptance of our terms and privacy policy. If you sign in with Google, we also receive the Google account identifier and profile details necessary to authenticate you.
• Learning data. We store the information needed to run the learning experience, including grammar progress, review history, vocabulary deck entries, bookmarks, lesson completion, activity history, and learning preferences.
• Subscription and access data. If you purchase Keystone Access or another paid offering, we receive subscription status and related entitlement metadata from the platform or billing providers that process the purchase. We do not receive your full payment card number.
• Technical and log data. We collect limited technical information needed to operate and secure the Services, such as IP address, timestamps, browser or app version, device information, and server or error logs.
• Audio and feature request data. When you ask the Services to play sentence or word audio, the text to be spoken may be sent to our audio providers and cached on our servers to improve speed and reuse. When you use certain optional AI-assisted features, the text you submit and the resulting exercise or language output may be processed by our AI service providers.
• Support and communication data. If you email us or contact us for support, we collect the information you include in that message so we can respond and help you.
• Guest mode and local device data. Some parts of the app can be used in guest mode. In that case, limited local learning state may be stored on your device until you sign in, delete the app, or clear app storage.

3. How we use information

• To create, authenticate, and maintain your account.
• To deliver lessons, review sessions, bookmarks, progress tracking, and personalized settings.
• To generate or play audio for lesson content and review content.
• To power optional AI-assisted language-learning features.
• To manage subscriptions, entitlement access, and account status across devices.
• To secure the Services, prevent misuse, debug problems, and maintain reliability.
• To respond to support requests and communicate with you about service-related matters.
• To improve the quality of lessons, exercises, performance, and product design.

4. Third parties and how we share data

We share personal information only when it is needed to operate the Services, comply with law, or protect users and the platform.

• Cloud hosting and infrastructure providers. We use cloud and hosting providers to run the backend, store data, and serve content.
• Authentication providers. Google may process sign-in requests when you use Google sign-in.
• Billing and subscription providers. Apple App Store, Google Play, RevenueCat, and Paddle may process purchase, entitlement, subscription, customer portal, and related billing information so we can unlock or maintain paid access.
• Audio providers. Google Cloud Text-to-Speech may process the text of lessons or review items when audio is requested.
• AI providers. OpenAI may process text submitted for certain optional AI-assisted learning features.
• Legal and safety disclosures. We may disclose information if required by law, court order, or valid legal process, or when necessary to protect users, Keystone Languages, or the public.
• Business transfers. If the business is reorganized, sold, or merged, information may be transferred as part of that transaction, subject to applicable law.

We do not sell personal information, and we do not use third-party advertising SDKs inside the Services.

5. Legal bases for processing

If you are in a jurisdiction that requires a legal basis for processing, we generally process information on one or more of the following bases:

• Contract. To provide the account, courses, lessons, review system, and paid access you request.
• Legitimate interests. To secure, maintain, improve, and support the Services.
• Consent. Where you choose an optional feature that requires it, or where law requires consent.
• Legal obligations. To comply with tax, accounting, security, or legal requirements.

6. Data retention

We keep personal information for as long as it is reasonably necessary to operate the Services, maintain your account, comply with legal obligations, resolve disputes, and enforce our terms.

• Account and learning data are generally retained while your account remains active.
• When you delete your account, we remove account records and related learning data from active systems, including vocabulary deck entries, review queues, review sessions, grammar progress, activity history, and preferences, subject to backup and legal retention limits.
• Cached audio files may persist for a limited period if they are not tied to your identity and are retained only to improve playback speed and service efficiency.
• We may retain limited records when required for legal, tax, fraud-prevention, or security reasons.

7. Security

We use technical and organizational measures designed to protect personal information. These measures include access controls, password hashing, and operational safeguards appropriate to the type of data we process.

No service can guarantee absolute security. You should also help protect your information by using a strong password, keeping your sign-in credentials private, and logging out of shared devices.

8. Your rights and choices

• Access and updates. You can update certain account details in the app.
• Delete account. You can delete your account in-app, or request deletion by emailing us.
• Subscription management. If you subscribed directly through Keystone Languages on the web, billing management is handled through our Paddle-powered customer portal. If you subscribed through Apple App Store or Google Play, cancellation and billing management are handled in your store account settings.
• Guest mode. If you use guest mode, clearing local app storage or uninstalling the app removes device-local guest data.
• Legal rights. Depending on where you live, you may have rights to request access, correction, deletion, restriction, objection, or portability. We will review and respond as required by applicable law.

9. International transfers

Keystone Languages and its service providers may process data in countries other than your own. Where required by applicable law, we use appropriate safeguards for cross-border transfers.

10. Children's privacy

The Services are not directed to children under 13, or the equivalent minimum age in the relevant jurisdiction, unless a parent, guardian, school, or other authorized organization uses the Services in compliance with applicable law. If you believe a child has provided personal information in violation of this policy, contact us and we will review the request.

11. Changes to this Privacy Policy

We may update this Privacy Policy from time to time. If we make material changes, we will update the date above and, where appropriate, provide additional notice inside the app, on the website, or by another reasonable method.

12. Contact us

If you have questions about this Privacy Policy, privacy requests, or account deletion requests, contact Keystone Languages at hello@keystonelanguages.com.