Last updated: July 4, 2026
GrammarWerk ("the App") is a language learning tool that generates grammar practice sentences. We respect your privacy and collect only the minimum data needed to provide the service.
GrammarWerk uses artificial intelligence (Anthropic Claude) to generate grammar practice sentences. All drill content is created on-the-fly by the AI model based on the grammar topic and CEFR level you select. Sentences are not pre-written or stored. The AI generates new sentences each time you request a drill.
Account information: When you create an account, we collect your email address and an encrypted password. This is used solely for authentication. An account is required to use the App: drills are generated on our servers, so you must be signed in to request one.
Usage data: We do not use analytics or third-party tracking tools, we do not build advertising or behavioral profiles, and we never sell your data. For rate-limiting purposes the backend logs an anonymously-hashed user identifier (a one-way hash that cannot be reversed to your email or name) and a request timestamp. The only practice activity tied to your account is the data you choose to sync (your saved drills, bookmarks, progress, and self-test scores); it is stored solely so it can follow you between your own devices, not to analyze your behavior. You can turn sync off at any time in Privacy & Data (see Cross-device sync below).
Sentence content: The sentences generated during your drills are created on-the-fly by an AI model (Anthropic Claude) and are not stored on our servers.
Local device storage: The App stores data on your device using standard browser storage (localStorage). This includes your theme preference, your most recent drill (so it is not lost if you switch apps), saved sentences you bookmark, your practice progress and self-test scores, and a record of which verbs you have practiced (to improve drill variety over time). Your device is always the primary copy of this data. By default it is also synced to your account (see Cross-device sync below); if you turn sync off, it stays only on your device. You can clear it at any time by clearing the app's data in your phone or browser settings.
Cross-device sync: Because using the App requires an account, your saved drills, bookmarks, practice progress, self-test scores, and lifetime practice counts are by default synced to your account so they follow you between devices (for example, between the Android app and the web app). You can turn this sync off at any time in Privacy & Data, in which case this data stays only on the device where it was created. Synced data can be deleted on its own or together with your account (see Delete Your Data below). Your theme preference, current language selection, and session state are never synced and always stay on-device.
Your email address is used only to authenticate your account. If you use cross-device sync, your synced practice data is used only to show your own drills, bookmarks, and progress on whatever device you sign in from, never to analyze your behavior or for advertising. We do not send marketing emails, share your information with advertisers, or sell your data to third parties.
The App uses the following third-party services:
user_sync table): Stores your email and encrypted password, and, when sync is enabled, your saved drills, bookmarks, practice progress, self-test scores, and lifetime practice counts. Supabase Privacy PolicyAuthentication data, and (when sync is enabled) your synced activity data, are stored on Supabase servers in the EU (Frankfurt, Germany). All communication between the App and our servers uses HTTPS encryption.
The App is not directed at children under 13. We do not knowingly collect data from children under 13.
You can delete some or all of your GrammarWerk data at any time — see "Delete Your Data" below for the exact steps for each option.
You can request deletion of your GrammarWerk data in two ways, both available from within the App:
We do not retain a copy of the deleted data after either action completes — there is no additional retention period. Sentence content generated during drills is never stored on our servers in the first place, so there is nothing to delete there. If you turn sync off without deleting, your data simply stays on your device; you can clear that local copy at any time by clearing the App's data in your phone or browser settings.
We may update this policy from time to time. Changes will be posted on this page with an updated date.
For questions about this privacy policy, contact: bradfrd12@gmail.com