Privacy by Design: Local-First EPUB Reading
At EPUB Reader Pro, privacy isn't just a feature—it's our foundation. Unlike cloud-based readers that upload your books to servers, we process everything locally in your browser. This approach ensures your reading habits, book content, and personal data never leave your device.
This privacy policy explains how we collect, use, and protect information when you use our service.
What Happens When You Open a Book
Your EPUB file is loaded directly into browser memory and parsed locally using the open-source epub.js library. No data is transmitted to our servers. Here's exactly what happens:
- Local Processing: All EPUB parsing, rendering, and navigation occurs in your browser
- No Uploads: Your book files never leave your device
- Client-Side Rendering: Text display, search, and annotations are processed locally
- Zero Data Transmission: No book content, reading progress, or personal data is sent to our servers
Information We Collect
We collect minimal information necessary for basic site functionality and improvement:
Technical Information
- Browser Information: Browser type, version, and capabilities for compatibility
- Device Information: Screen size and device type for responsive design
- Usage Analytics: Anonymous page views, session duration, and feature usage patterns
- Error Reports: Technical errors and crashes (without personal data)
Local Storage Data
All reading data is stored locally in your browser:
- Reading Preferences: Font choices, theme settings, layout preferences
- Reading Progress: Current position in books, bookmarks, and highlights
- Book History: List of recently opened EPUB files (filenames only)
- Annotations: Bookmarks, highlights, and notes you create
How We Use Information
We use collected information solely to improve our service:
- Service Improvement: Understanding which features are most used to guide development
- Technical Support: Diagnosing and fixing technical issues
- Performance Optimization: Identifying slow-loading features or compatibility issues
- Security Monitoring: Detecting and preventing potential security threats
Important: We never use your data for advertising, marketing, or sale to third parties.
Data Storage and Security
Local Storage Only
Your reading data is stored exclusively in your browser's localStorage:
- Device-Only Storage: Data never leaves your device
- Browser-Based: Tied to your browser and device
- User Controlled: You can clear data anytime via browser settings
- No Server Backup: We don't maintain copies of your data
Data Retention
Your data is retained according to this schedule:
- Reading Data: Stored until you clear browser data or uninstall the app
- Analytics Data: Aggregated and anonymized, retained for 24 months
- Error Logs: Retained for 30 days for debugging purposes
Information Sharing and Third Parties
We do not sell, rent, or share your personal information with third parties. Information is only shared in these limited circumstances:
Legal Requirements
- Court Orders: When required by law or valid legal process
- Legal Compliance: To comply with applicable laws and regulations
- Safety Protection: To protect against fraud, security threats, or harm
Service Providers
We may use third-party services for website hosting and analytics:
- Web Hosting: Vercel/Netlify for website delivery (no user data access)
- Analytics: Privacy-focused analytics tools (Google Analytics 4 with privacy controls)
- CDN: Content delivery networks for fast loading (no user data)
Your Rights and Controls
You have complete control over your data and privacy:
Data Access and Control
- View Data: Access all stored data through browser developer tools
- Export Data: Export bookmarks and highlights as JSON or Markdown files
- Delete Data: Clear all data by clearing browser localStorage
- Stop Using: Simply stop visiting the site to prevent further data collection
Privacy Rights
Under applicable privacy laws, you have the right to:
- Access: Request information about what data we collect
- Correction: Request correction of inaccurate data
- Deletion: Request deletion of your data
- Portability: Receive your data in a portable format
- Objection: Object to certain data processing activities
Cookies and Tracking
We use minimal cookies and tracking technologies:
Essential Cookies
- Session Management: Maintain your session while using the site
- Security: Protect against security threats and abuse
- Functionality: Remember your preferences and settings
Analytics Cookies
- Usage Tracking: Understand how the site is used (anonymized)
- Performance: Monitor site speed and reliability
- Opt-out Available: Disable analytics through browser settings
Children's Privacy
EPUB Reader Pro is not intended for children under 13. We do not knowingly collect personal information from children under 13. If we become aware that we have collected personal information from a child under 13, we will take steps to delete such information.
International Data Transfers
Since all processing occurs locally in your browser, no data is transferred internationally. Your reading data never leaves your device or jurisdiction.
Changes to This Privacy Policy
We may update this privacy policy from time to time. We will notify you of any changes by:
- Posting the new privacy policy on this page
- Updating the "Last Updated" date below
- Sending an email notification (if we have your contact information)
Your continued use of EPUB Reader Pro after any changes indicates acceptance of the updated policy.
Contact Us
If you have any questions about this privacy policy or our privacy practices, please contact us:
- Email: privacy@epubreaderpro.com
- Subject: Privacy Policy Inquiry
- Response Time: We aim to respond within 48 hours
Effective Date
This privacy policy is effective as of April 16, 2026.
Last Updated: April 16, 2026