Privacy Policy — Sudoku Axions

Publisher: AxionsLab inc. — corporation, 4-400 48e rue O, Québec (QC) G1H 5G6, Canada — NEQ 1233438649 Effective date: 27 October 2026 Contact: contact@axionslab.io

In one sentence

Sudoku Axions is played with no sign-up: no email, no name, no password. Your progress is stored on your device; our server only knows an anonymous account — a random identifier, the nickname you may choose, and your completed puzzles — to compute crowns and league leaderboards. We sell no data, and nothing in this game is ever paid for — in any form.

1. What is stored on your device

The game saves your progress to a file in the app's private storage on your device — a location other apps cannot read. It holds:

• the puzzle in progress, so you can pick it up where you left it;
• your statistics per difficulty (puzzles completed, best time, total time, mistake-free puzzles), the daily puzzles already done, your crowns and your hints;
• your day streak, validated days, weekly quests, your league and your crowns for the season;
• your settings: when mistakes are shown, vibration, language;
• your player identifier, drawn at random by the game on first launch. It contains nothing about you: no name, no address, no device identifier;
• your nickname, if you chose one;
• puzzles not yet sent to our server, and the last leaderboard received for your group (nicknames and crowns), so it can be shown offline;
• whether the screen explaining advertising has already been shown to you, and whether you were already asked about notifications, so we never ask twice.

Alongside that file, the game keeps the secret token of your online account (§5) and a technical log of gameplay events, capped at 2 MB, which never leaves the device.

Your advertising consent choice (§3) is stored on the device by the Google tool that collects it.

Uninstalling the game erases these files from the device. For the copy Android backup may keep in your Google account, see §6.

2. What we do not collect

We never request, read or store any of the following:

• name, postal address, email address, phone number — unless you write to us yourself (§8);
• hardware device identifiers (serial number, ANDROID_ID, MAC address);
• precise location;
• contacts, photos, microphone, camera, files;
• payment details — there are no purchases in this game, so there is nothing to pay with.

The only permission the game asks you for is to show notifications (§7), and you can decline it. The technical permissions it otherwise declares — internet access, advertising identifier (§3) — give no access to any of the data above.

3. Advertising

No video is forced on you. There are no interstitials, no full-screen ads and no videos between puzzles. The only videos in this game are rewarded videos that you choose to watch, by tapping a button that states the reward up front: a hint, three more mistakes when a puzzle has reached its limit, or the video that validates your day once the daily puzzle is done.

A small advertising banner is shown at the top of the puzzle screen. It never interrupts the puzzle.

These ads are served by Google AdMob. To display them, AdMob may process your device's advertising identifier and technical information (model, system, language, country, IP address).

• Google's policy: https://policies.google.com/privacy
• Your Google ad settings: https://adssettings.google.com

Your choice. If you live where the law requires it (the European Economic Area, the United Kingdom, Switzerland among others), a Google form (UMP, User Messaging Platform) asks for your consent, purpose by purpose, before any personalised advertising. You can change it at any time: Settings → Ad preferences. Elsewhere, that form is not shown and ads may be personalised; you can limit or reset the advertising identifier in your device settings.

Declining removes no reward: videos grant exactly the same thing, they are simply less targeted. The game states this commitment itself, on the consent screen and in its "Our promise" screen.

4. Analytics and crashes

To understand what works in the game and what blocks players, we record gameplay events. They describe actions, never people:

• app opens;
• puzzle started or resumed, and puzzle completed: its difficulty, how long it took, the number of mistakes, the crowns earned, whether it was the daily puzzle;
• hint used: the puzzle's difficulty and the solving technique shown;
• videos requested, completed or failed;
• day validated and streak length;
• your answer to the consent form;
• the Google Play review request (§8), with the number of puzzles completed and days played.

These events are processed by Google Firebase Analytics and attached to your player identifier (§1), never to your identity. They go to a Firebase project dedicated to Sudoku Axions, separate from our other games.

Consent first. Analytics is switched off at launch — including for the events Firebase sends on its own — and only opens with UMP's answer (§3): outside the areas where consent is required, it opens fully; inside them, it follows your choice, purpose by purpose (analytics, storage on the device, advertising use). Firebase applies those refusals through Google's "consent mode"; in particular, it only uses the advertising identifier if you accepted the advertising purposes.

We run no targeted advertising from this data, and we do not sell it. Identifier-level analytics data is kept for at most fourteen months at Google; only aggregated statistics remain afterwards.

Crashes. If the game crashes, Firebase Crashlytics receives a report: device model, system version, the technical state of the app at the time of the crash, and your player identifier, to link crashes together — never the content of your puzzle. These reports are used only to fix the game, and are sent whatever your advertising choice.

Google's policy: https://policies.google.com/privacy.

5. Online account and leagues

An anonymous account. The first time the game runs with an internet connection, it opens an account on our server: it sends your player identifier (§1), and the server hands back a secret token that then proves it is really you. No email, no name, no device identifier. Our server only keeps a cryptographic hash of the token.

What the server receives:

• your player identifier;
• your nickname, if you chose one;
• each puzzle you complete: the puzzle number, duration, number of mistakes, number of hints used, date, your day streak and the number of videos watched that day to validate it.

From those puzzles, the server computes your crowns, your group and your weekly league itself. It receives neither the content of your puzzles, nor your statistics, nor your hint stock, nor your settings, nor any device data. A puzzle started but not completed is never sent.

Like any server, it sees the connection's IP address; it uses it only in memory, to limit the number of requests, and does not store it in its database. Traffic is encrypted (HTTPS).

Your nickname. You can choose a nickname of 3 to 16 characters — letters and digits from any script, space, hyphen, underscore — in Settings → My nickname. It is sent to our server and visible to the other players in your group on the league leaderboard, with your crowns and rank. Without a nickname, you appear under a default name, "Player" followed by four digits derived from your identifier. Choose a nickname that does not identify you: no full name, no contact details.

Nicknames are not filtered automatically. If a nickname seems offensive or inappropriate to you, report it to contact@axionslab.io: we can erase it, and its owner then gets the default name back. There are no messages, photos or other player-written content.

Where. This server is run by AxionsLab at sudoku-api.axionslab.io, and hosted by Hetzner Online GmbH (Germany, European Union). Its database belongs to Sudoku Axions alone, separate from our other games. This data is kept for as long as the account exists: until you ask for it to be erased (§11), or at the latest twelve months after your last puzzle — an account that has sent no puzzle for a year is erased automatically, in the same way.

6. Google backup (Android)

Android offers automatic backup of apps to the phone's Google account. When it is on, your local progress (puzzle in progress, statistics, hints, streak, settings, nickname) may be copied there, then restored on a new device. That copy is managed by Google; we have no access to it.

The online account token and the technical log are excluded: on a new device, the game gets your progress back but opens a new online account, under a new identifier.

You can turn this backup off in your device settings (under Google → Backup, depending on the model).

7. Notifications

Notifications are optional. The game offers them once, after your third completed puzzle; if you decline, it never asks again. If you accept:

• a streak reminder, in the evening at 9 pm, when your day streak is at stake and today is not validated yet;
• once only, an absence reminder, on the third day without validating a day.

Never more than one notification a day. They are scheduled on the device by the game itself: no notification server, no data sent. You can turn them off at any time in your device settings.

8. Reviews and feedback

Google Play rating. After a few completed puzzles, the game may ask Google to show its official rating window. Google decides whether to show it, and your rating and comment go straight to Google Play: the game does not see them and does not pass them on to us.

"Send feedback" (Settings) opens your email app with a message addressed to contact@axionslab.io, prefilled with the game version, phone model, system version and language — not your player identifier, nor anything else personal. Nothing is sent until you send the message yourself. If you do, we then receive your email address and what you wrote; we use them only to reply, and erase the exchange on request.

9. Where your data is processed

• Our server: European Union (Germany), at Hetzner (§5).
• Google (AdMob, UMP, Firebase Analytics, Crashlytics, Android backup, Google Play): on its own servers, which may be outside Québec and Canada, notably in the United States, under its own protection commitments: https://policies.google.com/privacy.

Your information may therefore be communicated outside Québec.

10. Children

Sudoku Axions is intended for people aged 14 and over — in Québec, the law requires a parent's consent to collect information about a child under 14. It contains advertising. We do not knowingly collect data from a child; if you believe a child has sent us data, write to us and we will erase it.

11. Deleting your data, and your other rights

In the game: Settings → Delete my data. After confirmation, the game:

• erases from the device the save, its backup copy, the token and the technical log;
• asks our server to erase everything carrying your identifier: the account, nickname, puzzles received and league group places. Without a network, the request is kept on the device and sent again at every launch until the server confirms it;
• resets the device's Firebase analytics data.

The game then starts over, under a new identifier.

Outside the game — for instance if you uninstalled it — write to contact@axionslab.io with your player identifier and your deletion code (both shown in Settings → About). The code proves the request comes from you: the identifier alone is visible in leaderboards. We erase everything carrying the identifier on our server within 30 days at most. The full procedure is on the Support → Delete my data page: https://axionslab.io/games/sudoku-axions/support.

Data already sent to Google (analytics, crashes) is erased according to its retention periods (§4). The Android backup copy (§6) is replaced at the next automatic backup; you can also delete it from your Google account. An email you sent us (§8) is erased on request.

Your rights. Depending on where you live you have rights of access, rectification, erasure, objection and portability — Québec's Law 25, the GDPR in Europe, the Digital Personal Data Protection Act in India, and equivalents elsewhere. contact@axionslab.io is how to exercise them; include your player identifier, without which we cannot tell which data is yours. We reply within thirty days.

Person in charge of the protection of personal information: Jeremy Coquet, President of AxionsLab inc., reachable at contact@axionslab.io.

You may also lodge a complaint with Québec's Commission d'accès à l'information (https://www.cai.gouv.qc.ca) or your country's data protection authority.

12. Changes

Any change to this policy will be published on this page, with its date. If a change widens what we collect, it will be announced inside the game before it takes effect — not only here.