Privacy Policy
Effective May 24, 2026
This Privacy Policy describes how the G2G iOS app and the G2G browser extension (together, "G2G", "we", "us") collect, use, and share information about you when you use them. By using G2G, you agree to this policy.
1. What we collect
Account information
- Email address — when you sign in with email/password, Apple, or Google.
- Display name — provided by Apple or Google sign-in (you can leave this blank with Apple's "Hide My Email" option).
- Authentication tokens — issued by Firebase Auth; used to identify you on subsequent requests.
Content you create
- Vocabulary cards — the words and phrases you save, plus any context sentence, source URL, definitions, examples, translations, and notes you add.
- Review history — when you reviewed each card and how you rated it (Again / Hard / Good / Easy), used to schedule the next review via the SM-2 spaced-repetition algorithm.
- Generated articles — short daily articles G2G generates for you, plus their audio narration.
Settings and device data
- Language preferences — your native language, the languages you're learning, and your CEFR proficiency level.
- Notification preferences — whether notifications are enabled, what hour you want your daily push, and your time zone.
- Push notification token — a device-specific token from Firebase Cloud Messaging, used only to deliver notifications you've opted into.
What we do NOT collect
G2G does not use third-party analytics or advertising SDKs. We do not track your activity across other apps or websites. We do not sell your data.
2. How we use it
We use the information above to:
- Authenticate you and sync your data across devices.
- Generate your daily personalized article and reviews.
- Enrich newly-added vocabulary with definitions, examples, phonetic transcriptions, and visual memory hooks (see "Third-party services" below).
- Send the daily article push notification to your device at your chosen hour.
- Operate, maintain, and improve the app.
3. Third-party services
G2G uses the following third parties. We share only the data necessary for each service to function, and never user identifiers like your email.
| Service | Purpose | What's shared |
|---|---|---|
| Firebase / Google Cloud (Auth, Firestore, Storage, Cloud Messaging, Cloud Functions) | Account, data storage, notifications, server-side LLM proxying | Account email, vocab cards, review history, settings, push token |
| OpenAI | Generate definitions, example sentences, daily articles, audio narration | The word or phrase being looked up; the surrounding sentence if you provided one; the topic + CEFR level for article generation. Sent server-side only — your account identifier is not forwarded. |
| Giphy | Find a relevant meme/GIF for each vocab card | The word or phrase being searched. Sent server-side only. |
| YouGlish | Embed in-app pronunciation widget (in the iOS reader) | The word and target language, sent as URL parameters when you tap the pronunciation button. YouGlish loads inside an in-app webview — your G2G account is not linked. |
| BBC / The Guardian RSS | Seed daily articles with real news headlines | No user data — only the topic ID. Server-side only. |
These services have their own privacy policies. We encourage you to review them: Google, OpenAI, Giphy, YouGlish.
4. Data retention and deletion
We retain your account data as long as your account is active. To delete your account and all associated data, email guchengslash@gmail.com with the subject "Delete my G2G account" from the email address you signed up with. We will permanently delete your vocab cards, review history, audio files, and account record within 30 days.
You can also unsubscribe from notifications at any time in iOS Settings → Notifications → G2G, or in the in-app Settings tab.
5. Children's privacy
G2G is not directed at children under 13. We do not knowingly collect personal information from children under 13. If you believe a child under 13 has provided us with personal information, please contact us at guchengslash@gmail.com and we will delete it.
6. International users
G2G is operated from the United States. Your data is stored on Google Cloud servers (Firebase region: us-central1). If you access G2G from outside the United States, you consent to the transfer of your data to the United States.
European Economic Area, UK, Switzerland (GDPR)
You have the right to: access the personal data we hold about you, request correction or deletion, object to or restrict processing, and request portability of your data. Exercise these rights by emailing guchengslash@gmail.com.
California (CCPA)
California residents have the right to know what personal information we collect, to delete personal information we hold, and to opt out of the sale of personal information. We do not sell personal information. Exercise these rights by emailing guchengslash@gmail.com.
7. Security
We use industry-standard practices to protect your data, including HTTPS for all network traffic and Firebase's authentication system. No system is perfectly secure; we will notify affected users in the event of a breach involving personal data.
8. Changes to this policy
We may update this policy from time to time. We will post the new policy on this page and update the "Effective" date at the top. Material changes will be announced in-app or by email.
9. Contact
Questions, concerns, or requests? Email guchengslash@gmail.com.