Privacy Policy

Last updated: May 25, 2026

This service is a private EPUB translation tool. It is intended primarily for personal use, with possible access for invited users in the future.

What Data Is Stored

The application stores the following data in its MySQL database:

• User account information, such as email address, display name, account status, and login timestamps.
• Password hashes. Plaintext passwords are not stored.
• Login sessions, stored as hashed session tokens.
• Uploaded EPUB documents.
• EPUB internal files, markup segments, text segments, and metadata needed to rebuild the EPUB.
• Translation layers, including machine-translated or manually edited text.
• Imported translated EPUB text when using the Import translated EPUB feature.

Uploaded Documents

When you upload an EPUB, the application parses and stores its contents so it can display, translate, edit, and rebuild the document.

When you upload a translated EPUB for import, the application checks that its structure matches the original document and imports only the translated text segments into the existing document. It does not create a new document from that import.

Machine Translation Providers

If machine translation is enabled, document text segments may be sent to the configured translation provider, such as DeepL or AWS Translate.

Only the text needed for translation, together with source and target language information, is sent to the provider. The provider's own privacy policy and data handling terms apply.

If translation is disabled, no text is sent to an external translation provider.

Cookies and Sessions

The application uses a session cookie named epub_translator_session to keep users logged in.

The cookie is HTTP-only and uses SameSite protection. On HTTPS deployments, it should also be sent only over secure connections.

Session tokens are stored in the database only as hashes.

Logs and Error Reporting

The server may log technical errors and request failures for debugging and maintenance.

By default, users see short error messages. If verbose error output is enabled by configuration, error pages may include detailed exception information and stack traces. This should only be enabled in trusted environments.

Data Retention

Documents, extracted text, translations, and user accounts remain stored until they are deleted from the application or removed directly from the database.

Deleting a document removes its stored files, text segments, markup segments, and translations.

Expired or revoked sessions may be removed from the database.

Access Control

Documents are associated with user accounts. Users should only be able to access documents owned by their account.

The first setup user is an administrator. Existing unowned documents may be claimed by the first admin account during setup.

Security

The application stores password hashes instead of plaintext passwords and uses hashed server-side session tokens.

For public deployments, HTTPS should be used. If the application is behind a reverse proxy, the proxy should be configured to forward HTTPS information correctly, or the application should be configured to force secure cookies.

Third Parties

The application does not intentionally share data with third parties except:

• The configured machine translation provider, when translation is requested.
• Hosting, database, or infrastructure providers used to run the service.

Contact

For privacy questions or data deletion requests, contact the operator of this deployment.