Effective date: October 27, 2026 (previous: October 26, 2026 — we explained that messages sent from the in-app «Contact us» screen (message, optional email and app info) are handled by our own inquiry system, Duolink — Sections 1, 2 and 10.
The October 26 version, compared with October 21, added Google Firebase Analytics for anonymous usage analytics with your consent and clarified that crash diagnostics (Firebase Crashlytics) also apply to the iOS release.)
This Privacy Policy describes how DuoDuel ("the App", "we") handles information when you use our mobile application.
1. Summary
DuoDuel does not collect your name or other personal identifiers. There is no sign-up. We receive an email address only if you type it into the in-app «Contact us» screen, so we can reply (Section 2).
The table below is what the App actually does as of the effective date — it differs by platform.
"Not offered" means the corresponding data is not collected at all.
Feature
Android
iOS
Advertising (Google AdMob)
Shown (Section 3)
Shown (Section 3)
Account linking (Play Games)
Optional (Section 2)
Not offered
In-app purchases
Not currently offered
Not offered
Online matches
Available (Section 2)
Available (Section 2)
Anonymous analytics & error diagnostics
With consent (Section 2)
With consent (Section 2)
Usage analytics (Google Firebase Analytics)
With consent (Section 2)
With consent (Section 2)
Crash diagnostics (Google Firebase Crashlytics)
With consent (Section 2)
With consent (Section 2)
The iOS release ships without account linking or in-app purchases.
It shows ads but does not use the advertising identifier (IDFA) and does not request App Tracking
Transparency permission, and no progress wallet or player ID is created on our server.
What applies is on-device game data, anonymous analytics and error diagnostics if you consent
(Section 2 — these are retained as log records on our server), advertising (Section 3), and online match relay.
On Android, if you choose to link an account, our server stores your Play Games player ID and your
in-game progress (coins, diamonds, skins), plus a record of your first-launch consent, so it can be restored across devices (see Sections 2 and 6).
You can use every feature without linking.
2. Information We Handle
In-app inquiries — both platforms, only when you send one. When you send a message from Settings → «Contact us», the inquiry type and message, the email you choose to enter, the app version, operating system and version, and language the app attaches, and (if linked) your support code are sent to Duolink (duolink.co.kr), the inquiry system we operate ourselves, to answer you and check errors. To prevent excessive requests we store only hashes of your IP address and of an inquiry-only install value — this value is separate from the anonymous analytics install ID. Inquiries are kept for 1 year after the reply (Duolink privacy notice). Nothing is processed if you do not send an inquiry.
Optional account linking (Play Games) — Android only. Only if you choose to link, we receive a Google-issued Play Games player ID — an anonymous identifier, not your name or email — used to identify your progress wallet on our server. If you do not link, we do not collect this. The iOS release does not offer account linking.
Progress wallet — Android, only when linked. When linked, your coins, diamonds, owned skins, ad-removal status, and solo best scores are stored on our server alongside your player ID so they can carry across devices. If you do not link — and on iOS — these values are stored only on your device.
Consent record — Android, only when linked. The terms version you agreed to, when you agreed, your age confirmation, and your personalized-ads choice, together with the time our server received them, are kept on our server alongside your player ID. This lets us show what you agreed to and when; we keep the latest 20 entries per account and delete them with your progress wallet. If you do not link — and on iOS — this record is stored only on your device.
On-device data — both platforms. Game settings (sound, haptics), coins, diamonds, owned cosmetics, and best scores are stored only on your device and are removed when you delete the App.
Purchase verification — not applicable at present. The App does not offer any paid product on either platform, so no payment-related data — including purchase tokens and product IDs — is transmitted. If in-app purchases are re-enabled, this Policy will be updated and published with a new effective date first (see Sections 4 and 8).
Online matches — both platforms. When you use the online mode, a temporary 4-digit room code and in-game signals (such as moves) pass through our relay server in real time. This data contains no personal identifiers. To let you resume after a dropped connection, the moves of an ongoing match are held in server memory and are deleted when the match ends or after a short idle period; they are not written to disk.
Anonymous analytics & error diagnostics — both platforms, only with consent. To improve the service, app activity state, current game, play time, game results (win/loss), app version/platform, and app error reports are collected anonymously and retained as log records on our server. This data contains no personal identifiers and is not linked to any individual. If you decline on first launch, nothing is sent. To count sessions and users, we use a random per-launch session token that changes when the App restarts, and an anonymous per-installation ID generated randomly on your device after you consent. The installation ID is removed when you uninstall the App, and neither value is linked to or stored with a name, email, account ID, advertising ID, or hardware device identifier.
Usage analytics (Google Firebase Analytics) — both platforms, only with consent. To understand how the App is used and improve it, Google Firebase Analytics collects usage events (app launches and sessions, game starts, completions and results, ad views and rewards, in-game currency spending, purchase steps), device and app information (device model, OS version, app version, language, approximate region derived from IP address), and per-installation identifiers (app instance ID and Firebase installation ID). The advertising ID is not sent (ad-personalization signals are disabled), and no name, email, account ID or player ID is sent with it. The identifiers are removed when you uninstall the App. Nothing is collected unless you consent on first launch.
Crash diagnostics — both platforms, only with consent. When the App crashes or stops responding, Google Firebase Crashlytics collects technical information about the failure (stack trace, device model, OS version, app version, memory and disk state) and per-installation identifiers (Crashlytics installation UUID and Firebase installation ID). These identifiers are removed when you uninstall the App and are not linked to a name, email, account ID, or advertising ID. Nothing is collected unless you consent on first launch, and crash records left on the device before consent are deleted, not sent, when you consent.
International transfer — both platforms, only with consent. The usage analytics and crash diagnostics above are transferred outside your country as follows.
Countries: the United States and other countries where Google operates data centers
Items: (analytics) usage events, device model, OS version, app version, language, approximate region, app instance ID and Firebase installation ID; (crash diagnostics) stack trace, device model, OS version, app version, memory and disk state, Crashlytics installation UUID and Firebase installation ID
When and how: sent over an encrypted network connection while you use the App (analytics) or when a crash occurs (crash diagnostics), after consent
Retention: Google begins deletion 14 months after collection for analytics and 90 days after collection for crash diagnostics
How to refuse: do not consent on first launch; nothing is transferred (the App cannot be used without consent)
Advertising data — both platforms. The App displays banner and interstitial ads. To deliver them, Google AdMob collects data as described in Section 3. This data is collected by Google and is not stored on our server. The iOS release does not use the advertising identifier (IDFA).
3. Advertising
The App (Android and iOS) shows banner and interstitial advertisements provided by Google AdMob, a
third-party advertising service operated by Google. Analytics tools are used only with your consent — Google Firebase Analytics for anonymous usage analytics and Firebase Crashlytics for crash diagnostics — and neither uses the advertising ID (see Section 2).
No banners are placed on gameplay screens.
The iOS release does not use the advertising identifier (IDFA). Because it does not request
App Tracking Transparency permission, personalized ads are not shown, and ad performance is measured through Apple's
SKAdNetwork without identifying individuals. The advertising identifier listed below applies to Android only.
Data collected.
Advertising identifier (Android Advertising ID) — not used by the iOS release
Device and app information (device model, OS version, app version, language, network type)
Approximate location derived from IP address, used for ad relevance and regional compliance
Ad interaction data (impressions, clicks, and similar performance measurements)
Purpose. Serving advertisements (including personalized ads if you agree) and measuring ad performance.
Personalized ads (optional). The App requests personalized ads only if you agree to the [Optional] Personalized ads item on the first-launch screen.
You can use every feature without agreeing; in that case the App asks Google for non-personalized ads only (ads still appear).
You can agree or withdraw at any time in the App under Settings > Personalized ads. This item exists only in the Android release — the iOS release does not use an advertising identifier, has no personalized ads, and therefore does not ask; it requests non-personalized ads only.
Your choices. You can reset your advertising identifier or turn off personalized ads at any time in your
device settings — on Android: Settings > Privacy > Ads (menu names vary by device and Android version).
Turning off personalized ads does not remove ads; it makes them less relevant to you.
4. In-App Purchases (not currently offered)
As of the effective date the App offers no paid products on either Android or iOS. Coins and Diamonds
are free currencies earned through play; they cannot be bought with money or exchanged for money.
Accordingly no payment instrument details and no purchase tokens are sent to our server. (The app may
query the store for its product list; that communication happens only between the app and the store.)
A store listing may still display an "In-app purchases" label, but no purchase screen opens inside the App.
If in-app purchases are re-enabled, payments would be handled by the respective store's billing system
(Google Play / Apple App Store) and we would not collect or store payment instrument details. In that case
this Policy will be updated and published with a new effective date first (Section 8).
5. Children's Privacy
DuoDuel is not directed to children and is not designed or marketed as a child-directed app. On first launch the App asks you to confirm that you are 14 or older, and it cannot be used without that confirmation.
We do not knowingly collect personal information from children, and we do not knowingly process data subject to
COPPA (US), GDPR-K (EU), or similar children's privacy regulations. If you believe a child has provided such
information, please contact us using the details in Section 9.
6. Data Retention & Deletion
If you do not link an account — and on iOS — no progress wallet or player ID is
retained on our servers (anonymous analytics and error diagnostics, if you consented, are retained
as described in Section 2). On-device data (settings, coins,
diamonds, skins, scores) can be removed at any time via Settings → "Reset data" in the app, or by uninstalling.
If you have linked an account, the progress wallet and player ID stored on our server can be deleted on
request per our Data Deletion guide. Data collected by Google AdMob is retained and
deleted according to Google's own policies — see the Google Privacy Policy.
Usage analytics collected by Firebase Analytics are deleted by Google 14 months after collection, and crash diagnostics collected by Firebase Crashlytics 90 days after collection.
7. Security
All server communication is encrypted in transit (HTTPS/WSS). Online match traffic is limited to anonymous game
signals, and the progress wallet and player ID stored when you link an account are kept on an access-restricted server.
8. Changes to This Policy
If this policy changes, the updated version will be posted on this page with a new effective date, and material changes will be announced in the App.
9. Privacy Officer
Under Article 30 of the Personal Information Protection Act of the Republic of Korea, we designate the following person as responsible for personal data protection.