Last updated: 30 October 2026
Lezu ("the app") is published by appgrid.eu. Contact: lezu@appgrid.eu. We built Lezu to need as little data as possible. There are no ads, no third-party tracking and no device identifiers.
Everything you learn (progress, reviews, streaks, settings) is stored only on your device. You can delete it at any time in Settings → Reset progress, or by removing the app.
If you sign in (Sign in with Apple or Google), we receive a user id and, when you allow it, your e-mail address (Apple may give us a private relay address). Sign-in is handled by Google Firebase Authentication. Your learning progress is then synced to our own server in the Netherlands so you can use several devices. You can delete your account and all synced data in the app (Settings → Account → Delete account); deletion is immediate.
Messages you write to Tsiran are sent through our server to Anthropic (Claude) to generate a reply. We do not store the content of conversations; we only count messages and tokens per day to enforce the daily limit.
When you start a check, a short recording (a few seconds) is sent through our server to Microsoft Azure Speech for recognition. Recordings are not stored by us. The microphone is only used while you record.
"Report an error" sends your comment, the item id, the content version, your app language, app version and platform. Reports are anonymous unless you are signed in, in which case they are linked to your account id (removed when you delete your account).
Subscriptions are handled by Apple/Google and RevenueCat. We receive whether Premium is active and when it expires, never your payment details.
If enabled (Settings), the app sends anonymous product events such as "lesson completed" to our self-hosted Aptabase instance, without personal data, device ids or IP storage. You can switch this off at any time.
We process data to provide the app (contract) and, for statistics, based on our legitimate interest, which you can object to by switching it off. Synced data is kept until you delete your account; error reports are kept until handled, at most 24 months. Under the GDPR you may request access, correction, deletion or a copy of your data, and complain to the Dutch Data Protection Authority (Autoriteit Persoonsgegevens). Write to lezu@appgrid.eu.
Google Firebase (sign-in), Anthropic (AI replies), Microsoft Azure (speech recognition and voice audio), RevenueCat (subscription status), Apple and Google (app stores). Our server and database run in the Netherlands.
Lezu is suitable for all ages. The account and AI features are intended for users aged 16 and over, or younger with parental consent.