The short version. Prepstellar does not sell personal data, show ads or track you across apps or websites. The app uses the minimum data needed to keep your account and learning progress working, verify subscriptions, run optional analytics, diagnose failures and provide community and AI features. You can delete your account and linked data from inside the app.
Who is responsible
Oriol Dellà i Soler (trading as “Prepstellar”), NIF 77623436T, Barcelona 08013, Spain, is the data controller. Contact: support@prepstellar.com.
Where this policy applies
This policy covers the Prepstellar iOS and Android apps, prepstellar.com, the waitlist, support and the community features inside the app.
Data we handle
| Data | How we use it |
|---|---|
| Account identifiers. A Firebase user ID for every app session; optional email address and sign-in provider when you create a recoverable account. | Authenticate you, restore access on another device and delete the correct account. |
| Learning activity. Installed courses, answers, scores, favourites, review items, progress, streaks, study history and feature-usage counters. | Deliver the learning service, synchronise progress, enforce usage limits and improve aggregate course quality. |
| Profile and content you submit. Optional public nickname, community comments, blocked-user choices, support messages and error or content reports. Some in-app reports are deliberately stored without a user ID. | Operate and moderate the community, respond to support and correct course content. |
| Purchases. Product, transaction and subscription status associated with your app user ID. Apple or Google processes payment details; Prepstellar does not receive your full card number. | Unlock Premium, restore purchases and handle refunds or subscription status. |
| Device and technical data. A random installation/device identifier for signed-in device limits, platform, app version, integrity signals, crash logs, performance and diagnostic data. | Protect the service, cap active devices, troubleshoot faults and keep the app reliable. |
| Optional analytics. If you consent, app interactions, app/device information, the Firebase user ID and an approximate location (country or city level) that Google derives from your IP address are sent to Firebase Analytics. Collection is off until you choose, and can be disabled later in Settings. | Understand the onboarding, learning and purchase funnel and improve the product. |
| AI requests. Prompts and the relevant conversation or course context you choose to send to the tutor, coach or exam generator. | Generate the requested response and enforce usage quotas. The backend sends the request to Google Gemini/Vertex AI to provide the response and stores usage counters. If you choose “Report this answer”, we also store the reported answer, your related prompt, the reasons and comment you submit, course context and your user ID so we can review the report. |
| Website waitlist. Your email address and sign-up date if you joined before the launch (the list is closed to new sign-ups). | Send the launch notice you requested and record consent. |
Our hosting and security providers may also process standard request data, such as IP address and user agent, to deliver and protect the website and backend.
Why we may use it
Under the GDPR, we process service and account data to perform our contract with you or take steps you request (Art. 6.1.b); security, reliability, moderation and limited aggregate service measurement for our legitimate interests (Art. 6.1.f); analytics and the waitlist with your consent (Art. 6.1.a); and records we must retain to meet legal obligations (Art. 6.1.c). You are not subject to advertising profiling or decisions that produce legal or similarly significant effects.
Service providers and disclosures
We disclose data only as needed to operate Prepstellar: Google (Firebase Auth, Firestore, App Check, Analytics, Crashlytics, Cloud and Gemini/Vertex AI), RevenueCat (subscription entitlements), Apple and Google Play (store purchases), Hostinger (website hosting) and our email provider when we answer support or send the waitlist notice. They process data under their own terms or our processor agreements, as applicable.
We do not sell personal data, use it for third-party advertising, or track you across other companies' apps and websites. Public community comments and nicknames are visible to other users after moderation because that is the feature you chose to use.
International transfers
We select EU locations where the service supports them. Some providers may process data outside the European Economic Area. Where required, transfers rely on an adequacy decision, Standard Contractual Clauses or another lawful safeguard.
Retention and deletion
- Account-linked Firebase data is kept while your account exists and is deleted when you complete in-app account deletion.
- AI conversation text is not stored in Firestore during normal use. If you report an answer, the report stores that answer and its related prompt with your user ID. Reports linked to your user ID and quota counters are deleted with your account.
- Waitlist data is kept until the launch notice is sent or you ask for deletion.
- Operational diagnostics are kept only for the periods configured by the provider and needed to investigate reliability or security.
- Aggregated or anonymous statistics and reports that can no longer identify you may remain. Store, transaction or tax records may be retained where Apple, Google, RevenueCat or the law requires it.
To delete your account, open Account → Delete account in the app, type “delete” and complete re-authentication if requested. This removes the Firebase account, synced progress, profile, device registrations, usage counters, comments and reports linked to your user ID. Deleting an account does not cancel an active App Store or Google Play subscription; cancel that separately in the store. Full instructions and an email alternative are on our Delete account page.
Your choices and rights
You can use the app anonymously, turn usage statistics on or off at any time in Settings → Usage statistics, avoid community and AI features, or delete your account from Account → Delete account (details in Delete your data). Under the GDPR you may request access, correction, deletion, restriction, portability or object to processing. You may withdraw consent at any time without affecting earlier lawful processing. Email support@prepstellar.com; we will normally respond within one month.
You may complain to the Spanish supervisory authority, the AEPD, or your local authority. California residents may request access, correction or deletion and opt out of sale or sharing; Prepstellar does not sell or share personal information for cross-context behavioural advertising and will not discriminate for exercising a right.
Children
Prepstellar is a professional and technical exam-preparation service and is not directed to children under 16. If you believe a child has provided personal data, contact us so we can investigate and delete it.
Security and changes
Data is encrypted in transit. We use access controls, Firebase Security Rules, App Check and server-side entitlement checks, but no service can guarantee absolute security. We will update the date above when this policy changes and provide an appropriate notice if a change materially affects your rights.