LIPFLIP — PRIVACY POLICY
Last updated: October 2026
LipFlip (formerly LinguaFlip; "we", "us", "our") operates the LipFlip mobile application (the "App"). This Privacy Policy explains how we collect, use, and protect your information when you use our App.
By using LipFlip, you agree to the practices described in this Privacy Policy.
1. INFORMATION WE COLLECT
1.1 Account Information
When you create an account or sign in with Google, we collect:
• Your email address
• Your display name (if provided by your sign-in provider)
• A unique user identifier
This information is stored securely in Firebase Authentication and Firestore, operated by Google.
1.2 Learning Progress Data
We store your learning progress, including:
• Modules completed and current progress
• Daily streak data
• Practice history and statistics
• Language and level preferences
This data is associated with your account to sync your progress across devices.
1.3 User-Created Content
If you create custom flipbooks ("Own" flipbooks), the flashcard content you enter — the flipbook
title, and each card's sentence, translation, focus word and any note — is stored on your device
and synced to your account in Firestore, so your flipbooks are available on every device you sign
in on.
• This content is stored under your account and is readable only by you. Our security rules do
not allow one account to read another account's flipbooks.
• It is never used for advertising, profiling, or analytics, and is not shared with any third
party.
• When you delete a flipbook, its content is erased immediately and only a deletion marker (the
flipbook's internal identifier and the time of deletion) is kept for up to 30 days, so the
deletion also reaches your other devices. That marker is then removed automatically.
• A copy is also kept on your device, so your flipbooks keep working offline.
1.4 Friends: Username, Profile Photo and Connections
LipFlip lets you connect with other learners. For this:
• Every account has a username. It is created automatically from the part of your email
address before the "@" (for example, anna.k@example.com becomes "anna.k"), with a number
added if that name is already taken. You can change it at any time in your Profile.
• Your username is visible to every signed-in LipFlip user and can be found by searching for
it. Your email address itself is never shown to other users, and nobody can search for you by
email.
• You may add a profile photo. It is stored as a small image in Firestore and is visible only to
you and the people you are connected with.
• A connection needs both sides to agree: one person sends a request, the other accepts it. If
you refuse a request, the sender is not told.
• Once connected, each of you sees the other's username, photo, total points, current streak,
which of the last seven days were practiced, and the language practiced last. To work out
which day it is for you, the time zone of your device is shared with your friends' app as well.
Your progress in individual lessons, your settings and your email are never shared.
• A friend can send you a reminder ("poke") at most once every 12 hours. If you allow
notifications, we store a push notification token for your device so the reminder can be
delivered through Firebase Cloud Messaging. The token is removed when you sign out.
• You can remove a friend, block a user (which ends the connection and stops their requests and
reminders) or report a user. A report stores who reported whom, the reason and an optional
note, and is used only to enforce our Community Guidelines.
1.5 API Keys (Bring Your Own Key)
If you choose to enter your own API keys for Google Gemini or Unreal Speech:
• These keys are stored ONLY on your device in local storage
• They are NEVER transmitted to our servers, logged, or stored in any database
• Keys are sent directly from your device to the respective third-party API provider
1.6 Voice Data
When you use speech recognition features:
• Audio recordings are processed in real-time for pronunciation evaluation
• Speech recognition is performed by your device's own recognizer. Depending on your device and
settings, it may process audio on-device or via your operating system's speech service
(Apple on iOS, Google on Android)
• Audio is never sent to LipFlip. We do not store, retain, or have access to your voice recordings
• Audio is processed transiently and discarded after recognition
1.7 AI Conversation Data
When you use the AI conversation practice feature:
• Your spoken input (converted to text) is sent directly to Google Gemini for AI response generation
• We do not store conversation transcripts on our servers
• Conversations are processed in real-time and are not retained after your session ends
1.8 Diagnostic Reports (optional, only when you send one)
The App keeps a short activity log on your device to help diagnose problems such as speech
recognition failures. This log stays on your device and is never uploaded automatically.
If you choose to send a diagnostic report — by tapping "Send diagnostic report" in Settings, or
"Send diagnostic info" when the App offers help after failed speech attempts — we receive:
• The most recent portion of the activity log (up to 300 lines)
• Your app version, platform, device model as reported by your browser/WebView, and your
selected native and target languages
• An optional note you write yourself
Please note:
• The activity log can include sentences you spoke during practice, because that is what makes
a speech-recognition problem diagnosable. The exact text to be sent is shown to you in full
before you send it.
• API keys and email addresses are automatically removed from the log before it is sent
• Nothing is transmitted until you review the report and tap Send. There is no automatic,
background, or crash-triggered upload.
• Reports are stored in Firestore under your account and are used only to investigate and fix
the problem you reported. They are never used for advertising, profiling, or analytics.
• Reports are automatically deleted 30 days after they are sent
2. HOW WE USE YOUR INFORMATION
We use the information we collect to:
• Provide and maintain the App's functionality
• Track and display your learning progress
• Authenticate your identity
• Manage internal service access and usage quotas
• Investigate and fix problems in diagnostic reports you choose to send us
• Let you find, connect with and remind your friends, and review reports about abusive users
• Improve the App's features and user experience
We do NOT use your information for:
• Advertising or ad targeting
• Selling to third parties
• Data mining or profiling
• Marketing communications (unless you opt in)
3. THIRD-PARTY SERVICES
LipFlip integrates with the following third-party services. Each has its own privacy policy:
3.1 Firebase (Google)
• Purpose: Authentication, user data storage, cloud functions, push notifications (Firebase
Cloud Messaging) for friends' reminders
• Data shared: Account information, learning progress, Friends information (section 1.4), your
device's push notification token if you allow notifications, and any diagnostic report you
choose to send
• Privacy Policy: https://firebase.google.com/support/privacy
3.2 Google Gemini
• Purpose: AI conversation practice
• Data shared: Text input for conversation (sent directly from your device)
• Privacy Policy: https://ai.google.dev/gemini-api/terms
3.3 Unreal Speech (optional)
• Purpose: High-quality text-to-speech
• Data shared: Text to be spoken (sent directly from your device)
• Privacy Policy: https://unrealspeech.com/privacy
When using BYOK (Bring Your Own Key), API calls go directly from your device to these providers using your personal API key. We have no visibility into these requests.
4. DATA STORAGE AND SECURITY
• Account and progress data is stored in Google Firebase (Firestore) with security rules that restrict access to authenticated users viewing only their own data — except for the Friends information described in section 1.4: your username is visible to signed-in users, and your photo and practice statistics only to the people you are connected with
• API keys are stored exclusively in your device's local storage
• We use HTTPS for all network communications
• Firebase Authentication handles secure sign-in
• We do not store passwords — authentication is handled by Google's identity platform
5. DATA RETENTION
• Your account data is retained as long as your account is active
• Learning progress data is retained as long as your account exists
• Custom flipbooks you create are retained until you delete them or delete your account; a
deleted flipbook's content is erased immediately, and the deletion marker that carries the
deletion to your other devices is removed automatically after 30 days
• Voice recordings are not retained — they are processed transiently
• AI conversation data is not retained after sessions end
• Diagnostic reports you choose to send are automatically deleted after 30 days
• Your username, photo, connections, requests and reminders are kept until you change or remove
them, or delete your account; deleting your account removes all of them, including reports
you filed and reports about you
• You can request deletion of your account and all associated data at any time
6. YOUR RIGHTS
You have the right to:
• Access the personal data we hold about you
• Request correction of inaccurate data
• Request deletion of your account and data
• Export your learning progress data
• Withdraw consent for data processing
To exercise any of these rights, contact us at the email address provided below.
7. CHILDREN'S PRIVACY
LipFlip is designed as an educational tool and is suitable for users of all ages. We do not knowingly collect personal information from children under 13 without parental consent. Connecting with other users in Friends requires confirming that you are at least 13 years old. If you are a parent or guardian and believe your child has provided personal information without your consent, please contact us.
8. DATA TRANSFERS
Your data may be processed in countries where Google operates its Firebase infrastructure. By using the App, you consent to the transfer of your information to these locations. Google complies with applicable data protection frameworks for international data transfers.
9. CHANGES TO THIS PRIVACY POLICY
We may update this Privacy Policy from time to time. We will notify you of any material changes by posting the new Privacy Policy within the App or through other appropriate communication channels. Your continued use of the App after changes constitutes acceptance of the updated policy.
10. CONTACT US
If you have questions or concerns about this Privacy Policy or our data practices, please contact us at:
Email: rexervit@gmail.com
Website: https://linguaflip.org
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This privacy policy applies to the LipFlip mobile application available on Google Play Store and Apple App Store.
THE WEBSITE (linguaflip.org)
The website has no user accounts. It may store one cookie named "linguaflip_language" to remember the language you explicitly choose for the website.
• We set this cookie only when you actively select a language or use the ?lang= parameter.
• The cookie lasts for 180 days.
• This cookie is used only for language preference. It is not used for advertising, profiling, analytics, or cross-site tracking.
• You can remove it at any time in your browser settings.