Jack English — Privacy Policy
Effective date: 10 October 2026
ValentineOS ("we", "us") develops the Jack English app (published on Google Play as "English Grammar", "the App"). This policy explains what data the App processes, why, who it is shared with, and how you can delete it. By using the App you agree to this policy.
1. You can use the App without an account
Grammar topics, tests, the dictionary and reminders work without signing in. In that case your data stays on your device and we do not receive any personal information.
2. Data stored on your device
• Learning progress: topics marked as known, test results and daily practice history.
• Your personal dictionary: words, translations, folders and pictures you take with the camera or choose from your gallery.
• App settings (theme, language, reminder time, chosen translator).
The dictionary and its pictures never leave your device unless you share a folder yourself as a file. Uninstalling the App removes all of this data.
3. Account (optional)
If you create an account we process:
• your email address;
• your name, if you provide it;
• your password — it is stored only in hashed form by our authentication provider, we never see it;
• if you sign in with Google (or with Apple on iOS), the email address and name that service shares with us.
We use this data only to sign you in, keep your account secure and send account emails (sign-up confirmation, password reset, email change).
4. Cloud sync
When you are signed in, your learning progress (topics marked as known, test results and daily practice counts) is stored with your account, so you can restore it after reinstalling the App or continue on another device. Your dictionary is not synced.
5. Online features and service providers
We share data only with the providers needed to run these features:
• Supabase (Supabase, Inc.) — accounts, storage of synced progress and delivery of test content.
• Google and Apple — only if you choose to sign in with them.
• Translation in the dictionary — the word or phrase you translate is sent to our translation servers (translate.valentineos.pp.ua, nllb.valentineos.pp.ua) or, if they are unavailable, to MyMemory (Translated srl). Only the text being translated is sent.
• AI assistant — messages you type in the chat are sent through our server to OpenAI to generate a reply. They are not linked to your account. Please do not enter personal information in the chat.
Pronunciation uses the text-to-speech engine on your device. Links to our social media pages open external websites that have their own privacy policies.
These providers may process data on servers outside your country, under their own privacy policies and appropriate safeguards.
6. Permissions
• Internet and network state — sign-in, sync, translation, downloading tests.
• Camera — only when you take a picture for a dictionary word.
• Notifications — study reminders; they are scheduled on your device.
• Files / storage — importing and exporting dictionary folders that you choose.
7. What we do not do
The App shows no ads, does not use the advertising ID and contains no analytics or tracking tools. We do not sell your data and do not share it with anyone except the providers listed above.
8. Security
All data is sent over encrypted connections (HTTPS). Cloud data can be accessed only with your account, and the sign-in session is kept in your device's secure storage. No method of transmission or storage is completely secure, but we take reasonable measures to protect your data.
9. Data retention and account deletion
We keep your account data for as long as your account exists.
Delete in the App: Settings → Account → Delete account. Your account and all its cloud data are deleted immediately and permanently, together with the learning progress and dictionary on that device.
Delete without the App: email jackenglishgrammar@gmail.com from the address of your account with the subject "Delete account". We will delete the account and all its data within 30 days and confirm by email.
10. Your rights
You can request access to, correction, export or deletion of your personal data, or object to its processing, by contacting us. You can also lodge a complaint with your local data protection authority.
11. Children
The App is intended for users aged 13 and over. We do not knowingly collect personal data from children under 13. If you believe a child has created an account, contact us and we will delete it.
12. Changes to this policy
We may update this policy when the App changes. The new version is published in the App and on our website with a new effective date. Continued use of the App after an update means you accept the revised policy.
13. Contact us
ValentineOS, Vinnytsia, Ukraine
jackenglishgrammar@gmail.com