Information We Collect

We collect the following types of information:

• Account information: email address and display name provided during registration. If you sign in with Google or Apple, we receive your name and email address from the provider.
• Study progress: flashcard review history, spaced repetition scheduling data, study statistics, and custom cards you create.
• Device and usage data: device type, operating system, app version, and error/crash reports to help us improve the service.
• Payment information: on the web, payment details are processed directly by Stripe. On mobile, in-app purchases and subscriptions are managed through the Apple App Store or Google Play Store via RevenueCat. We store only subscription status and entitlement information — payment credentials are never stored on our servers.
• Analytics data (web only): anonymized page views and performance metrics (such as page load times) are collected to improve site performance. No personally identifiable information is included.

How We Use Your Information

We use the information we collect to:

• Provide and maintain the Waffuru service
• Schedule your flashcard reviews using the FSRS algorithm
• Track your study progress and display statistics
• Process subscription payments
• Diagnose and fix technical issues via error reports
• Improve app performance through anonymized analytics
• Communicate important service updates

Data Sharing

We do not sell, rent, or trade your personal information to third parties. We share data only with the service providers listed below, and only to the extent necessary to operate Waffuru. We do not share your data for advertising or marketing purposes.

Third-Party Services

We use the following third-party services to operate Waffuru. Each processes data on our behalf and is governed by their own privacy policy:

• Supabase — authentication and database hosting. Stores your account, study progress, and settings.
• Sentry — error tracking and performance monitoring. Receives crash reports and diagnostic data. Sensitive fields (authentication tokens, cookies) are redacted before transmission.
• Stripe — payment processing for web subscriptions. Processes your payment method directly; we never receive or store your full card details.
• RevenueCat — in-app purchase and subscription management for iOS and Android. Receives your anonymous user identifier and purchase receipts from Apple or Google to verify subscription status.
• Vercel — web hosting, anonymized analytics, and performance monitoring (web only). Collects anonymized page views and Core Web Vitals metrics.
• Expo (EAS) — mobile app build and over-the-air update delivery. Receives device platform and app version metadata to deliver updates.
• Apple / Google — OAuth sign-in providers and app store payment processors. We receive only your name and email when you choose to sign in with these services.

Cookies and Local Storage

On the web, we use cookies and browser local storage solely for authentication session management and storing your theme preference. We do not use tracking cookies or third-party advertising cookies. On mobile, authentication tokens are stored in encrypted device storage.

Data Security

We take reasonable measures to protect your information, including encryption in transit (HTTPS/TLS) and at rest. Authentication tokens on mobile are stored using platform-provided encrypted storage. Sensitive data is redacted from error reports and logs. However, no method of electronic transmission or storage is 100% secure, and we cannot guarantee absolute security.

International Data Transfers

Your data may be processed and stored on servers located outside your country of residence, including in the United States. Our service providers maintain appropriate safeguards for cross-border data transfers in compliance with applicable law.

Children's Privacy

Waffuru is not directed at children under the age of 13 (or 16 in the European Economic Area). We do not knowingly collect personal information from children. If you believe a child has provided us with personal information, please contact us at support@waffuru.com and we will promptly delete the information.

Data Retention

We retain your data for as long as your account is active. If you delete your account, all associated personal data (profile, study progress, custom cards, and subscription records) will be permanently removed in accordance with our Data Deletion Policy. Error reports in Sentry are retained for up to 90 days. Anonymized analytics data does not contain personal information and is not subject to deletion requests.

Your Rights

Depending on your jurisdiction, you may have the following rights regarding your personal data:

• Access: request a copy of the personal data we hold about you
• Correction: request correction of inaccurate data
• Deletion: request deletion of your data (see our Data Deletion Policy). You can delete your account directly within the app.
• Portability: export your data in a portable format (Anki-compatible deck export)
• Objection: object to processing of your data for certain purposes

To exercise any of these rights, please contact us at support@waffuru.com. We will respond within 30 days.

California Privacy Rights (CCPA)

If you are a California resident, you have the right to know what personal information we collect, request its deletion, and opt out of any sale of personal information. We do not sell personal information. To make a request, contact us at support@waffuru.com.

Do Not Track

Waffuru does not track users across third-party websites. We do not respond to Do Not Track browser signals because we do not engage in cross-site tracking.

Changes to This Policy

We may update this Privacy Policy from time to time. We will notify users of significant changes by posting a notice within the application. Your continued use of Waffuru after changes are posted constitutes acceptance of the revised policy. The date at the top of this page indicates when the policy was last updated.

Contact

If you have questions or concerns about this Privacy Policy, please contact us at support@waffuru.com.