Last updated: 12 August 2026
The short version:
Your learning record is stored on your device; signing in adds an optional cloud backup of your progress.
You can use Lexeum without an account. There are no ads, and we never sell your data.
Usage analytics and crash reports are on by default and can be switched off in Settings.
News notifications are opt-in.
This policy explains what data Lexeum ("we", "us") collects, why, and the choices you have. It applies to the Lexeum mobile app and to lexeum.app. Lexeum is operated by Lexeum Private Limited, a company registered in Mumbai, India.
Your detailed learning record — word progress, exercise results, review schedule, streaks, session state, and app preferences — is stored locally on your device. Signing in uploads a backup of part of it (section 2); separately, when usage analytics is enabled, the app sends the usage events described in section 4. You can erase your local learning data at any time from Settings ("reset progress" — this clears progress, results, review scheduling, session state and streak, but not your preference toggles) or by uninstalling the app.
Lexeum works fully without an account. If you choose to sign in — with Google or Apple, via Firebase Authentication — we receive and store:
The backup contains your word progress, exercise results, review schedule, current streak and last-session date — not your session state or preferences. We use it solely to back up your progress, restore it on a new device, and link your subscription across devices. Deleting your account in Settings removes the backup and the account itself; section 9 describes exactly what deletion does and does not reach.
Lexeum Pro is billed by Apple's App Store or Google Play. We never see or store your payment card details — payment is handled entirely by the store. To know whether your subscription is active, we use RevenueCat, a subscription management service acting as our data processor. RevenueCat processes your purchase history, subscription status, an app user identifier (random, or linked to your account identifier if you sign in) and basic device information, on servers in the United States.
We use Google Firebase Analytics and Firebase Crashlytics to understand how the app is used and to fix crashes. When enabled, this records usage events — sessions started, resumed, completed or abandoned (with exercise counts and accuracy); each exercise answered, with the word and whether you were right; words introduced, entering review or mastered; screens viewed; paywall visits, purchases, restores and their failure reasons; sign-ins and content-sync outcomes — together with user-level properties (words learned, current streak, subscription status) that we use for audience measurement and campaign targeting, plus device and app-version information. Crashlytics receives crash traces and related device information.
This data is pseudonymous: it is keyed to a Firebase app-installation identifier rather than to your name or email, and we do not attach your account identity to it. On Android, Firebase may also receive the device's advertising ID unless that collection is disabled. Collection is on by default and you can turn it off at any time in Settings → "Anonymous analytics and crash reports"; switching it off stops future collection.
The app uses additional Google Firebase services to function: Firebase Storage (downloading new word content), Remote Config (feature settings), App Check (abuse prevention through device attestation), Performance Monitoring and In-App Messaging. These process technical device data as part of operating the service. Data processed by Firebase and RevenueCat may be stored on servers outside your country, including in the United States; both providers commit to recognised safeguards (such as standard contractual clauses) for international transfers.
lexeum.app does not set cookies and contains no analytics or advertising trackers. Our hosting provider may process ordinary request data — IP address, browser and device information, requested URLs, timestamps and security logs — to deliver and protect the site. If you email us, including to ask for early access, we receive your email address and message and use them to reply and, where you asked for early access, to send you early-access and launch updates; email us to leave that list at any time.
Directly in the app: sign out; delete your account; reset local progress; and switch analytics, reminders and news notifications on or off.
Deleting your account in Settings deletes your Firebase Authentication account and your Firestore backup, and clears the learning progress on the device. It does not cancel an App Store or Google Play subscription, and it does not remove transaction records held by the stores; RevenueCat subscription records and analytics or crash data already collected may also persist until separately deleted or until their retention periods expire. Email support@lexeum.app to request deletion of any remaining data that can be linked to you.
Depending on where you live — including under the EU/UK GDPR and California's CCPA/CPRA — you may have rights to access, correct, delete, or receive a copy of your personal data, to object to or restrict processing, to withdraw consent (without affecting earlier lawful processing), and to complain to your data protection authority. California residents may act through an authorised agent and may not be discriminated against for exercising their rights; we do not "sell" or "share" personal information as the CCPA defines those terms. We will apply India's Digital Personal Data Protection Act and its rules as their provisions take effect. To exercise any right, email support@lexeum.app; we respond within the timelines applicable law requires.
Lexeum is not directed at children under 13 (or the higher minimum age your country requires for consent to data processing). We do not knowingly collect personal data from children. If you believe a child has provided us personal data, contact us and we will delete it.
Data is encrypted in transit, stored with reputable providers (Google Cloud, AWS via RevenueCat) and protected by access controls. No system is perfectly secure, but we keep the data we hold to a minimum. We retain account data and backups until you delete your account. Firebase retains crash reports for around 90 days and user-associated analytics data for a limited period (no longer than 14 months) before deletion or aggregation. Early-access email addresses are kept until you ask to leave the list. Transaction and subscription records may be retained by the app stores and RevenueCat for their own operational and legal purposes.
We will post any changes on this page and update the date above. For material changes we will also give notice in the app.
Lexeum Private Limited
CIN: U85500MH2026PTC471872
Registered office: 1st Floor, 1B-102, Parinee Crescenzo, G Block, Bandra Kurla
Complex, Bandra (East), Mumbai 400051, Maharashtra, India
Phone: +91 99879 37884
Questions, requests, or grievances (including under India's IT Rules, and the DPDP Act as its provisions take effect):
support@lexeum.app. We aim to acknowledge
grievances within 48 hours and resolve them within applicable statutory timelines.