Privacy Policy

Last Updated: June 2, 2026

This Privacy Policy explains how Klug ("App", "we", "us", "our") collects, uses, and protects your information.

1. Information We Collect

Your Learning Data

The following data is stored on your device and, when you sign in with Apple, is also synced to your private account in our cloud (Firebase / Google Cloud) so it is available across your devices. If you use the App as a guest (without signing in), this data stays only on your device and is not transmitted to our servers (except if you choose to send a feedback report):

• Anonymous User ID: A randomly generated identifier stored on your device. It is not linked to your real identity.
• Learning Progress: Completed lessons, spaced repetition queue, and review history.
• User Profile: Your selected proficiency level, learning goals, and daily targets.
• Learner Intelligence: Patterns in your mistakes and areas for improvement, used to personalize your experience.
• Student Facts: Information you share during AI conversations (e.g., interests, goals) that helps personalize future interactions.
• Notes: Any notes you save from lessons or conversations.
• Credit Balance: Your credit balance and transaction history.
• App Settings: Your preferences for AI provider, conversation depth, and other settings.

Information Shared with Third-Party AI Providers

When you use AI-powered features (AI Teacher chat, Speaking Buddy), the following is sent to our AI providers to generate responses:

• Your messages: The text or transcribed speech you send in conversation.
• Learning context: Your proficiency level, recent lesson topics, and common mistakes (no personally identifying information).
• Conversation history: Previous messages in the current conversation session for context.

We use AI providers including Anthropic (Claude), Google (Gemini), and Mistral AI (Mistral). Each provider has its own privacy policy governing how they handle data.

Audio Data

When you use the Speaking Buddy feature, your microphone input is processed by Apple's on-device speech recognition. Raw audio is not stored or transmitted to our servers. Only the transcribed text is used.

Feedback Reports

If you choose to submit a feedback report, it may include:

• Your proficiency level
• Recent navigation history (screen names only, not content)
• App version and device model
• Your written description of the issue

2. How We Use Your Information

• Personalization: Adapting lesson difficulty, AI responses, and review schedules to your level and progress.
• AI Conversations: Providing contextually relevant responses in Teacher and Speaking Buddy features.
• Fact Extraction: After AI conversations, we may use AI to identify learning-relevant facts you've shared (e.g., "interested in travel", "struggles with dative case") to improve future personalization. You can opt out of this in Settings.
• Spaced Repetition: Scheduling vocabulary reviews at optimal intervals based on your performance.
• Bug Fixing: Using feedback reports to identify and resolve issues.

3. Data Storage and Security

• Learning data (progress, profile, notes, learner intelligence, student facts, and preferences) is stored locally on your device and, for signed-in users, synced to your private account in Firebase Firestore (Google Cloud) so it is available across your devices. Guest data remains only on your device.
• Cloud services: The App uses Firebase Authentication for Sign in with Apple and Firebase Firestore to store your synced learning data, credit balance, and feedback reports. This data is stored on Google Cloud servers.
• AI conversation metadata (provider used, token counts, timestamps) is logged to Firestore for billing purposes and automatically expires after 90 days.
• Data is not encrypted at rest beyond iOS device-level encryption and Firebase's default encryption.
• Deleting the App removes all locally stored data. To delete cloud-stored data (account, credits, feedback), use "Delete All Data" in Settings or contact us.

4. Third-Party Services

• Apple App Store — Purchases and subscriptions. Payment is handled entirely by Apple.
• Anthropic (Claude) — AI Teacher and Speaking Buddy responses. Data shared: conversation messages, learning context.
• Google (Gemini) — AI responses and fact extraction. Data shared: conversation messages, learning context.
• Mistral AI (Mistral) — AI responses (if selected as provider). Data shared: conversation messages, learning context.
• Apple Speech Recognition — Voice input transcription. Audio is processed on-device by Apple's speech framework.
• Google Firebase — Authentication, database (Firestore), cloud functions, and file storage. Data shared: your account identifier; for signed-in users, your synced learning data (progress, profile, learner intelligence, student facts, notes, preferences); credit balance; feedback reports; purchase transaction records. Data is stored on Google Cloud servers in accordance with Google's data processing terms.

5. Children's Privacy

The App is not directed at children under 16. We do not knowingly collect personal information from children under 16. If you believe a child under 16 has provided us with personal information, please contact us so we can delete it.

6. Your Rights

• Access: You can view all data the App stores about you in the Profile and Settings screens.
• Deletion: Use "Delete All Data" in Settings to permanently erase all locally stored data.
• Portability: Your data is stored locally and can be accessed through iOS device backups.
• Opt-Out of Fact Extraction: You can disable personalized fact extraction in Settings.

7. Data Retention

• Local data is retained until you delete it or uninstall the App.
• AI conversation data sent to Anthropic is retained for up to 30 days per their usage policy. Google (Gemini) and Mistral retain data per their respective privacy policies.
• Firebase Authentication records are retained until account deletion.
• Firestore data (credit balance, feedback reports) is retained until you use "Delete All Data" in Settings or contact us at neo.can@gmail.com.
• AI conversation metadata logged for billing purposes automatically expires after 90 days.
• Feedback reports are retained only as long as needed to resolve the reported issue.

8. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of material changes through the App. Continued use after changes constitutes acceptance.

9. Contact Us

For questions about this Privacy Policy or your data, email neo.can@gmail.com or use the "Report an Issue" feature in the app (Profile → Settings → Report an Issue).

10. California Residents (CCPA)

If you are a California resident, you have the right to know what personal information we collect, request deletion, and opt out of sale of personal information. We do not sell personal information.

11. European Residents (GDPR)

Data Controller: Klug App, operated by Can Ozel. Contact: neo.can@gmail.com or use the "Report an Issue" feature in the app (Profile > Settings > Report an Issue).

If you are in the European Economic Area, you have rights under the GDPR including access, rectification, erasure, restriction, portability, and objection.

Legal bases for processing:

• Consent — AI-powered features (Teacher chat, Speaking Buddy, Fact Extraction). You can withdraw consent at any time by disabling these features in Settings.
• Legitimate interest — Providing core app functionality, personalizing your learning experience, and improving the App.
• Contract performance — Processing purchases and delivering purchased credits.

To exercise your rights, email neo.can@gmail.com or use the "Report an Issue" feature in the app (Profile → Settings → Report an Issue). We will respond within 30 days.