Math Chain — Privacy Policy

1. Summary

• Math Chain does not ask you to create an account and does not ask for your name, email address, contacts, photos or precise location.
• Your game progress, coins, settings and the optional player name you type in are stored only on your device. We do not run servers that receive them.
• The game shows ads from Google AdMob. Google may collect your device's advertising ID, IP address and similar data to show, limit and measure ads and to prevent fraud.
• Optional purchases are processed by Google Play. We never see your payment details.
• When you first open the game, it shows a privacy notice. In the EEA, the United Kingdom and Switzerland it also asks for your advertising consent through Google's consent form.

2. Who is responsible

Math Chain is developed and published by Rodion Saveliev, a sole proprietorship registered in Poland, trading as Bazovik Studio ("we", "us"). We are the data controller for the processing described in this policy, except where it is stated that Google acts as an independent controller.

• NIP: 9452337027 · REGON: 545851279 · Country: Poland
• Privacy contact: rodion.saveliev.dev@gmail.com

3. Data the game handles

The table below lists everything the game handles. "On device" means the data never leaves your phone through us.

We do not use analytics, crash-reporting or social SDKs in Math Chain, and we do not sell personal data.

4. Advertising (Google AdMob)

Math Chain shows interstitial ads between rounds and optional rewarded video ads (for example, to continue after losing). Ads are served by Google AdMob, provided by Google Ireland Limited (EEA/UK users) and Google LLC. Google acts as an independent controller for the data it collects through its SDK. See How Google uses information from sites or apps that use its services and the Google Privacy Policy.

• Legal basis. In the EEA, the UK and Switzerland, personalised ads are shown only with your consent (Art. 6(1)(a) GDPR), collected through Google's consent form. Without consent, Google may still show non-personalised ads, which rely on limited data for frequency capping, aggregated reporting and fraud prevention (our legitimate interest in funding a free game, Art. 6(1)(f) GDPR).
• Change your choice. If the consent form applies to you, open Settings → Ad privacy options in the game at any time.
• Advertising ID. You can reset or delete your advertising ID, or opt out of personalised ads, in your device settings under Settings → Google → Ads (Android 12+), or Settings → Privacy → Ads.
• Remove Ads. The one-time "Remove Ads" purchase turns off interstitial ads. Rewarded videos you choose to watch remain available.

5. In-app purchases

Coin packs and one-time items are sold through Google Play Billing. Payment is handled entirely by Google Play under the Google Privacy Policy and Google Play terms. We receive only the information needed to deliver the item — the product ID, the order status and a purchase token — never your card details, name or billing address. The game keeps purchase tokens on your device so that items are not delivered twice, and asks Google Play to restore one-time purchases after a reinstall.

6. Data stored on your device

Your progress, coin balance, unlocked themes and avatars, daily bonus streak, settings, language, the optional player name you type in, and simple counters of in-game events (such as runs started) are saved in the game's private storage on your phone. They are not sent to us or to anyone else. Clearing the app's data or uninstalling the game deletes them permanently.

7. App permissions

• Internet and network state — to load ads and talk to Google Play for purchases. The puzzle itself plays offline.
• Vibrate — for optional haptic feedback, which you can switch off in the game's settings.
• Advertising ID (com.google.android.gms.permission.AD_ID) — added by the Google Mobile Ads SDK so ads can use the advertising ID, as described in section 4.

The game does not request access to your location, camera, microphone, contacts, photos or files.

8. Sharing and international transfers

We do not share personal data with anyone other than the Google services described above. Google may process data outside the European Economic Area, including in the United States. Google relies on the EU–US Data Privacy Framework and Standard Contractual Clauses for these transfers. We may disclose information if required by law.

9. Security

Data collected by Google's SDKs is transmitted over encrypted connections (HTTPS/TLS). Data saved by the game stays in Android's app-private storage, which other apps cannot read. Because we do not operate servers that receive player data, there is no player database on our side that could be breached.

10. Retention and deletion

• On-device data is kept until you clear the app's data or uninstall the game; either action deletes it immediately.
• Advertising data is retained by Google according to its own policies (see How Google retains data). Resetting or deleting your advertising ID breaks the link to previously collected ad data.
• Purchase records are kept by Google Play as part of your Google account's order history.
• Emails you send us are kept for as long as needed to answer you, and for no more than 2 years after the conversation ends unless the law requires longer.

To ask us to delete data or to ask a question about deletion, write to rodion.saveliev.dev@gmail.com. We will reply within 30 days. As we hold no player data on our servers, in most cases uninstalling the game is enough to remove everything we would hold.

11. Children

Math Chain is a general-audience puzzle game and is not directed at children under 13. We do not knowingly collect personal data from children. If you believe a child has provided personal data through the game, contact us at rodion.saveliev.dev@gmail.com and we will help remove it.

12. Your rights

Under the GDPR you have the right to access your personal data, have it corrected or erased, restrict or object to its processing, and receive it in a portable format. Where processing is based on consent, you may withdraw consent at any time (see section 4) without affecting earlier processing. Write to rodion.saveliev.dev@gmail.com. For data collected by Google, you can also use the tools in your Google Account. You may lodge a complaint with the President of the Personal Data Protection Office (UODO), ul. Stawki 2, 00-193 Warsaw, Poland, or with the supervisory authority where you live.

13. Changes to this policy

We will update this policy when the game changes the way it handles data — for example if a new SDK is added. The current version is always published at this address with its date shown above. If a change is significant, the game will show the privacy notice again so you can review it.

14. Contact

Rodion Saveliev (Bazovik Studio), Poland · NIP 9452337027 · Privacy and support: rodion.saveliev.dev@gmail.com

The privacy policy for the studio website is published separately on the website privacy policy page.