READTWIN · Privacy
Privacy notice
How this version handles books, settings, translation requests and feedback. Updated 13 October 2026.
Local library
Imported ebook files, reading progress, notes, vocabulary and translations are stored in this device’s browser using IndexedDB and localStorage. Browser storage is not a permanent backup; clearing site data can remove it.
Translation and AI features
Translation, definitions and AI guides send the required text and a small amount of context to this site’s server, which forwards it to the configured AI provider. The updated translation endpoint does not persist private book text or API keys in its translation database. Provider retention is governed by that provider’s policy.
Personal API keys
Personal API keys are stored unencrypted in this browser’s localStorage. Requests forward the key through this site’s server to your chosen endpoint. Other device users, extensions or malicious scripts may access browser storage. Use a trusted device and remove keys when no longer needed.
Operational data and limits
The public translation service uses hashed client identifiers and expiring counters to control usage. Counters contain no book text. The hosting server, network proxy and AI provider may maintain operational logs. The current home page does not proactively send book titles or filenames to the legacy upload audit endpoint.
Backups and optional sync
Exported backups contain books, notes, vocabulary and translations, but not AI keys. If you configure WebDAV, sync or backup sends relevant content to your chosen WebDAV service, with authorization relayed through this site’s server.
Feedback and voluntary donations
Feedback you submit, its category, interface language and optional email are saved on the server for up to 180 days, privately for the administrator. Books, reading content and API keys are not automatically attached. Limits use short-lived hashed identifiers. Once PayPal donations are enabled, following the payment link opens PayPal, which handles payment information.
Your controls
You can remove books, clear translation caches, export a backup, or delete this site’s storage through browser settings. Language preferences use local storage and require no advertising cookies. Chinese fonts may load from the jsDelivr CDN.
Browser storage can be cleared by your browser. Export a backup regularly.