Cardbud Privacy Policy

Overview

This Privacy Policy explains how Cardbud ("the App", "we", "us", or "our") accesses, collects, uses, shares, protects, retains, and deletes information when you use the App on Android or iOS.

Cardbud helps users create flashcards, study language material, ask an AI tutor questions, import notes, process PDFs, recognize text from images, transcribe audio, and sync or back up study progress when users sign in.

Information We Collect or Process

Depending on which features you use, the App may collect or process:

• Account information, such as email address, display name, password credentials, email verification status, and account verification or password reset codes.
• Learning content, such as decks, flashcards, review history, study progress, preferences, notes, chat prompts, AI responses, and generated flashcards.
• Uploaded files or media, such as PDFs, images, and audio recordings that you choose to import.
• Image text, audio transcription results, PDF parsing results, and other AI-generated outputs created from content you provide.
• Purchase-related information, if paid features are available, such as product identifiers, purchase status, subscription status, and hashed Google Play purchase tokens used to verify access.
• Analytics and product usage information, such as feature usage events, onboarding progress, entitlement status, error information, device/network metadata, and approximate technical identifiers needed to operate, secure, debug, and improve the App.

The App requests access to the camera, photo library, microphone, and files only when needed for features you choose to use.

How We Use Information

We use information to:

• Provide AI tutoring, flashcard generation, text recognition, PDF parsing, and audio transcription features.
• Create and manage your local or service-backed study content.
• Sync or back up your decks, cards, review history, preferences, and learning progress when you sign in.
• Verify your email address, send account verification or password reset codes, authenticate accounts, and protect access to user data.
• Verify purchase status and provide paid entitlements if paid features are available.
• Analyze product usage, diagnose errors, maintain, debug, secure, and improve the App and backend service.

Sharing and Third-Party Service Providers

We do not sell personal information. We may share or process information with service providers only as needed to operate the App, including:

• OpenAI, for AI responses, text recognition, flashcard generation, and transcription features.
• Render, for hosting the backend API.
• PostHog, for product analytics and usage measurement.
• Google Play Billing, if paid features are available, for purchase and subscription verification.
• Apple, Google, or Expo services as required for app distribution, device features, and platform operation.

Content you send to AI-powered features, including text, images, PDFs, audio, transcriptions, and generated prompts, may be transmitted to OpenAI to generate responses or outputs. Please avoid submitting information you do not want processed by these services.

Analytics events sent to PostHog are used to understand feature usage and improve the App. We do not intentionally send raw flashcard content, passwords, or full account credentials to analytics services.

Local Guest Mode and Cloud Sync

If you use local guest mode, some learning content may remain only on your device unless you use online features such as AI tutoring, import processing, analytics, or account sign-in. If you sign in, your decks, cards, review history, preferences, learning progress, entitlement information, and related account data may be stored on our backend service so the App can sync or restore your content.

Data Security

We use HTTPS for communication with the backend service. Passwords are stored using salted password hashing. We limit access to operational secrets, such as API keys, through server-side environment variables.

No method of transmission or storage is perfectly secure, but we take reasonable steps to protect the information processed by the App.

Data Retention and Deletion

We retain account and study data for as long as needed to provide the App's features, comply with legal obligations, resolve disputes, verify purchases, prevent abuse, and maintain security. Temporary uploaded files may be processed only for the requested feature and then discarded.

You can delete your account from the App's Profile or Account settings when signed in. You may also request deletion of your account or data by using the contact method listed below or the support contact listed in the App Store or Google Play listing. Deletion removes account data and associated server-backed study data where applicable. Some operational logs, backups, purchase records, or security records may be retained for a limited period where required for legal, security, fraud-prevention, or payment verification reasons.

Children's Privacy

The App is not intended for children under 13. If you believe a child has provided personal information through the App, please contact us so we can take appropriate action.

Your Choices

You can choose not to use features that require camera, photo library, microphone, or file access. You can also manage device permissions in your operating system settings.

Changes to This Policy

We may update this Privacy Policy from time to time. When we do, we will update the "Last updated" date above. Continued use of the App after changes means the updated policy applies.

Contact

App: Cardbud

For privacy questions, data access, or deletion requests, please contact us at xirong.zhang.ly@gmail.com or through the support email listed in the App Store or Google Play listing for Cardbud.