Your EPUB stays on your device.

epubcover is designed so the book file does not need to be sent to an application server.

Local file processing

When you choose an EPUB, browser code reads the ZIP package in this tab. The cover preview, image conversion, XML updates, package rebuild, and final download all happen on your device.

What is not collected

• Your EPUB file or cover image
• Book title, author, filename, or file hash
• The contents of chapters, metadata, or embedded media

Temporary browser memory

The selected files and generated Blob URLs remain in browser memory only for the current page session. Resetting, refreshing, or closing the tab releases that working state.

Verification

You can open the Network panel in your browser developer tools while processing a file. The application does not make an upload request containing the EPUB or cover.