Privacy policy

Chompbook (in Russian: «Грызи») · Effective 26 October 2026

Chompbook is a learning app made by Oleg Tsarkov ("we"). In short: your learning data stays on your phone. We run no accounts, no analytics and no ads. Text leaves the phone only to go to the AI service you choose, to us when you report a lesson, or to a web page you ask the app to read.

1. Data kept only on your device

• Your skillsets, the books, articles, notes and courses you import, lessons, answers, progress, XP, streaks and badges.
• Your name (as you typed it), daily goal, interface language, theme and reminder time.
• An age group (under 13, 13–17 or 18+) if you connect an AI service. The birth year itself is not stored.
• AI service keys, kept in the phone's secure storage (Android Keystore / iOS Keychain).
• An error log and your lesson reports, until you send or clear them.
• Automatic backups in the app's storage and, before updates, in Documents/PES on the phone.

We have no copy of this data and cannot see it.

2. AI services you connect

AI features are optional. If you connect an AI service (for example Google Gemini, Anthropic Claude, OpenAI ChatGPT, Groq, Mistral, OpenRouter, NVIDIA, Yandex Alice AI, Alibaba Qwen, or your own server), the app sends that service, directly from your phone and with your own key: excerpts of your materials, the skillset name and goal, your quiz results and the open answers you ask it to check. The service processes this under its own terms and privacy policy, which you accept when connecting it. On some free tiers the service may use this content to improve its models — the app tells you so before you connect. Do not upload personal or confidential documents.

Google sign-in (only to create a free Gemini key for you): with your consent the app signs in to your Google account once, creates a "Chompbook" project with a key restricted to the Gemini API, and signs out. The access token, your e-mail address and your name are not stored.

3. Lesson reports

When you tap the flag to report a lesson, the report contains: the reason you picked, your optional comment, the text that was on the screen, the lesson title, which AI service and model wrote it, and the app version. Anything that looks like an API key is removed. Reports are saved on your phone; when you tap "Send to developer", your mail app opens with the report filled in, addressed to support@chompbook.online, and it is sent only when you press Send. We use reports only to review the content and improve the app. We keep reports for up to 12 months.

4. Other network requests

• Web pages you add as sources are downloaded from their sites.
• Update check (only in the version installed from GitHub): once a day the app asks GitHub for the latest release. The version from Google Play is updated by Google Play.
• Like any internet request, these reveal your IP address to the server you contact.

5. What we don't do

• No accounts, no tracking, no advertising, no analytics or crash-reporting SDKs.
• We don't sell or share your data.

6. Your choices

• Use the app without AI (Settings → Lesson mode → "Always without AI").
• Remove an AI key at any time in Settings.
• Delete everything: Settings → Delete all data, or uninstall the app.
• Export your data: Settings → Export backup.
• To have a lesson report deleted, write to us.

7. Children

The app is intended for users aged 13 and over. Users under 13 cannot connect AI services; lessons from their own materials work without sending anything. Users aged 13–17 may connect only services that allow their age, with a parent's or guardian's permission where the service requires it.

8. Security

Data in transit is encrypted with HTTPS (except a server address you enter yourself starting with http://, such as a computer on your home network). Keys are kept in the phone's secure storage.

9. Changes

We will publish any changes on this page and update the date above.

10. Contact

Oleg Tsarkov · privacy@chompbook.online