Privacy Policy

Effective: 14 July 2026 · česká verze

This policy describes how the Coeff mobile app ("the app") handles data. It complies with EU Regulation 2016/679 (GDPR).

In short: Coeff has no sign-up and no accounts. We don't ask for your name, e-mail or phone number. Your settings and picks stay on your device. The only thing leaving the app is anonymous technical communication with Google (data downloads, push notifications, ads).

1. Data controller

The app is operated by Karel Zbíral, a natural person based in the Czech Republic.

Contact: info@coeff.app
Web: https://coeff.app

We have no Data Protection Officer (DPO) — as a natural person we are not subject to that obligation.

2. What data is processed

2.1 Data stored only on your device

Followed country — which country you want highlighted
App language and theme
Picks and saved scenarios of the "What if…?" calculator

This data is stored locally only (SharedPreferences) and is never uploaded anywhere. Uninstalling the app deletes it.

2.2 Downloading competition data

The app downloads public data (match results, draws, rankings) from Google's Firebase Realtime Database (region europe-west1, EU). With every such request Google technically processes the device's IP address — same as when visiting any website. We have no access to IP addresses and never link them to a person.

Legal basis: legitimate interest (delivering up-to-date data).

2.3 Push notifications (optional)

Anonymous FCM device token (Firebase Cloud Messaging)
Subscribed topics — the code of your followed country (e.g. "zeme_CZE")

The token is not linked to any identity — we don't know whose device it is. You can turn notifications off in the app's Settings or in the system settings; uninstalling the app invalidates the token.

Legal basis: performance of contract (delivering a feature you enabled).

2.4 Advertising (Google AdMob)

Purpose: showing ads that fund the app's operation
Data: anonymised advertising ID of the device, IP address, ads shown
Consent: before personalised ads a consent dialog (Google UMP) is shown. If you decline, you only see contextual ads with no profiling.
More: policies.google.com/technologies/ads

Ads can be temporarily disabled by watching a short video, and we plan a cheap yearly subscription to remove them entirely.

Legal basis: consent (personalisation), legitimate interest (contextual ads).

3. What we do NOT collect

no sign-up, e-mail, name or phone number,
no location (GPS),
no contacts, photos or files,
we never sell any data to third parties.

4. Processors

The only processor is Google (Firebase platform — Realtime Database, Cloud Messaging; and AdMob for ads). Data is processed on EU servers; transfers outside the EU rely on Standard Contractual Clauses (SCC). More: firebase.google.com/support/privacy.

5. Retention

Local data — until you uninstall the app.
FCM token — while notifications are on; invalidated by uninstalling.
Advertising data — per Google's policies (links above).

6. Your rights under GDPR

You have the right of access, rectification, erasure, restriction, portability and objection. Since we keep no personal data about you, most rights are fulfilled simply by uninstalling the app. For anything else write to info@coeff.app — we reply within 30 days. You may lodge a complaint with your local supervisory authority (in the Czech Republic: uoou.gov.cz).

7. Children

The app is not directed at children under 13. We do not knowingly collect personal data from anyone — the app doesn't ask for any.

8. Changes

If anything substantial changes (e.g. a new feature working with data), we will update this page and change the effective date above.