Legal

Privacy Policy

Effective date: April 17, 2026

Braintain ("we", "us", or "our") operates the Braintain mobile application and the website at braintain.app. This Privacy Policy explains what personal data we collect, why we collect it, and how we protect it. By using Braintain you agree to this policy.

1. Information We Collect

Account information

When you register, we collect your email address and a hashed password to authenticate you. You may optionally provide a display name.

Learning data

We store the flashcard decks (BrainPods) you create or join, your study progress, spaced-repetition ratings, card maturity levels, study streaks, and session statistics. This data is essential to deliver the core functionality of the app.

Usage analytics

We collect anonymised events such as cards studied, sessions started, and features used. This helps us understand how people learn with Braintain and improve the product. No personally identifiable information is attached to these events.

Device and technical information

We may collect your device type, operating system version, app version, and crash reports to diagnose issues and maintain stability.

Purchase information

If you subscribe to Braintain Premium, the transaction is processed by Apple App Store or Google Play. We receive only a subscription status token — your payment details are never transmitted to or stored by Braintain.

2. How We Use Your Information

We do not sell your personal data to third parties.

Provide, maintain, and improve the Braintain service
Personalise your spaced-repetition schedule and study recommendations
Send optional push notifications to remind you of due cards
Respond to support requests
Detect and prevent fraud or abuse
Comply with legal obligations

3. Third-Party Services

Firebase (Google)

We use Firebase Authentication for sign-in and Cloud Firestore to store your learning data. Google's privacy policy applies to data processed by Firebase: https://policies.google.com/privacy

Google AdMob

Free-tier users may see ads served by Google AdMob. We request non-personalised ads only, which means your data is not used to build an advertising profile. You can remove ads entirely by subscribing to Braintain Premium.

RevenueCat

We use RevenueCat to manage in-app subscriptions across iOS and Android. RevenueCat receives your anonymised device ID and subscription status. Their privacy policy is available at https://www.revenuecat.com/privacy

Vercel

Our website (braintain.app) is hosted on Vercel, which may log standard web server data such as IP addresses and browser user-agent strings for security and performance purposes.

4. Data Retention

We retain your account and learning data for as long as your account is active. If you delete your account, we will delete your personal data within 30 days, except where we are required to retain it by law.

5. Your Rights

Depending on where you live, you may have the right to:

Access the personal data we hold about you
Correct inaccurate data
Request deletion of your data
Object to or restrict certain processing
Data portability (receive your data in a machine-readable format)

To exercise any of these rights, contact us at the address below. We will respond within 30 days.

6. Children's Privacy

Braintain is not directed at children under 13 (or under 16 in the European Economic Area). We do not knowingly collect personal data from children. If you believe a child has provided us with personal data, please contact us and we will delete it promptly.

7. Security

We use industry-standard measures to protect your data, including TLS encryption in transit and Firebase security rules to restrict data access. No method of transmission or storage is 100% secure, and we cannot guarantee absolute security.

8. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of material changes by updating the effective date above and, where appropriate, via in-app notification. Continued use of Braintain after a change constitutes acceptance of the updated policy.

9. Contact

If you have questions about this Privacy Policy or your personal data, please contact us at privacy@braintain.app.