We store: your email and display name, your uploaded books and their processed output (private to you), your study progress (vocabulary mastery, quiz history, reading progress), your token ledger, and — if you add one — your own LLM endpoint configuration (API keys encrypted at rest).
Study sessions send passage text and your messages to the configured LLM backend (ours, or your own endpoint if you set one). We don't sell or share your data.
Deleting your account (Settings, or DELETE /api/account) removes your books, uploads, study state, and endpoints immediately. Accounting records are retained without your identity.
Questions or rightsholder notices: the operator