Privacy Policy

1. The one question the app asks

The first time Math Empire opens it asks a single question — what year were you born — and offers "I'd rather not say" as a real answer. Nothing tells the player which answer leads where, nothing is refused, and whatever the answer is, the game opens.

The answer stays on the device. It is written to the device's own storage and is never sent to us or to anyone else. It is used on the device to decide two things:

Anything we are not sure about is treated as a child. If the answer cannot be read, or the part of the app that stores it fails to load, the app falls back to showing no ads and offering no sign-in — never the other way round. Because only the year is known and not the birthday, age is rounded down: a whole birth year is only treated as 13 once everyone born in it has certainly turned 13.

This describes current versions of the app. The age question was added partway through the app's life, and a device still running a build from before it does not have it. If you are not sure, update Math Empire from Google Play — the current version is the one this policy describes.

2. What is collected

The browser game at mathempire.app/play/

It asks for no name, no email address and no sign-in, and it shows no advertising to anyone. It keeps progress on the device and backs it up to our server under a randomly generated save key — a string of random characters with nothing personal in it — so that clearing a browser does not have to mean lost work. What is backed up is the practice record (which math facts have been met and how they are going) and story progress.

The Android app

• A display name — the ruler name the player types in. They choose it; it does not have to be their real name.
• A Player Code — a randomly generated code such as SKY8234, used to identify the save without an account.
• Game progress — coins, buildings, streaks, the chosen grade level, the chosen mentor and character, and the mastery record of which math facts have been practised.
• An email address and a Google account ID — only if a player aged 13 or over chooses to sign in with Google. Under-13 players are never shown that button.
• Usage events — a small fixed list such as "app opened", "problem solved", "building placed", "session ended". Each event carries a two-letter country code, which our network provider works out from the connection.
• Error diagnostics — when something goes wrong: the error message, the app version, the device and browser identification string, the screen the player was on, the Player Code, and a short scrambled form of the IP address the report came from. We do not store the address itself. We will not call that scrambling anonymous, because it is not strong enough to deserve the word — it is there to let us count distinct devices, not to make the address unrecoverable.
• Feedback sent from inside the game. In the Android practice room it carries the display name; in the island adventure it carries no name, no code and no identifier at all — only what was tapped and the technical details of the device shown on that screen.
• Classroom membership — if a child joins a class with a teacher's code: the class, the name the teacher sees, and the progress attached to it.

A newsletter address is collected only if someone types one into the form on this website.

Math Empire does not collect contacts, photos, microphone input, camera input, precise location, or card and payment details. It has no chat, no messaging and no player profiles, so there is no way for anyone to contact a child through the game.

On the coarse-location point, so it is not a surprise: we do not collect GPS or any precise location, but the country code on usage events is worked out from the network connection, and so is the scrambled address on an error report. Both are listed above rather than hidden behind "we do not collect location".

3. Advertising

Players under 13 are shown no advertising of any kind. Not a banner, not a rewarded video, and not the offer of one. This is not a setting or a preference: for a player who has not told us they are 13 or over, Google's advertising software is never started — no request is made, nothing is loaded, and the ad code is never reached. The same is true for a player who chose "I'd rather not say" and for one who has not answered the question yet. A test that loads the shipped app code and fails if any advertising call is made for an under-13 player runs against every change.

Players 13 and over may be shown a banner, and may choose to watch a rewarded video, through Google AdMob — unless they have bought the ad-free upgrade, which removes them.

Those ads run without an advertising ID. The Android advertising-ID permission is removed from the app altogether, so no advertising identifier exists for anything to be targeted with. We are wording this as the permission fact rather than claiming the ads are "non-personalised", because the permission is the part we have actually done and can point at. We do not send Google any profile of a player, and we do not build one.

Choosing a higher school grade to get harder math does not change any of this. Advertising follows the birth year the player gave, and nothing else.

4. Google Sign-In

Signing in is optional and is only offered to players 13 and over. If a player signs in, we receive the name on the Google account, the email address, and a Google user ID, and we use them for one thing: linking the save so it can be recovered on another device. We do not read anything else from the Google account. Google's Privacy Policy governs the sign-in itself.

Under-13 players are not shut out of moving between devices — the anonymous Player Code does the same job without an email address.

5. Analytics and crash reporting

The Android app includes Google Analytics for Firebase and Firebase Crashlytics. They send Google a record of app usage — screens opened, the fixed list of game events, the app version, the chosen grade band, mentor and character, whether the ad-free upgrade is active — and, when the app crashes, a crash report describing the device and the fault.

Being straight about the part that matters: this currently runs for every player of the Android app, including players under 13. It is tied to an identifier Google generates for the app installation, not to a name; the Android advertising ID is switched off for it, so it cannot be joined to advertising profiles. For a player who has signed in with Google, an identifier derived from their email address is also attached. We are changing the app so that under-13 players are left out of analytics in the same way they are already left out of advertising. Until that ships, this sentence is what happens, and we would rather write it down than have you find it.

The browser game has no analytics or crash reporting in it at all.

We also keep our own record of the usage events listed in section 2 on our own server. It is plain counting — how often a screen is opened, how many problems were solved — and it is not used for advertising or sold to anyone.

6. What it is used for

• Saving progress and restoring it on another device.
• Choosing which math facts to review next, and at what level.
• Leaderboard positions and, for a teacher, the class view.
• Finding and fixing crashes and bugs.
• Understanding which parts of the game are used, so the next part is built in the right place.
• Scheduling the optional reminders described in section 10.

It is not used to target advertising, to build a profile of a player, or to sell or rent to anyone. We do not sell data.

7. Who else it reaches, and where it is kept

Our own copy lives in a database on a server we rent in Los Angeles, California, United States. Everything sent between the app and that server travels over HTTPS. To be exact rather than reassuring: the data is not encrypted field-by-field once it is in the database — the display name, the Player Code, the saved progress and, for a signed-in player, the email address are stored as ordinary text on a server only we can log in to.

There are no other analytics, tracking or advertising services in Math Empire, and no data broker or advertiser receives anything from us.

8. How long it is kept

• The account and its saved progress — for as long as the account is in use, and until it is deleted. Deletion is immediate on request.
• Usage events — 90 days, then deleted automatically by a nightly job.
• Error diagnostics — written to a log file per day, and files older than 30 days are deleted automatically each night. One exception we would rather name than let you assume otherwise: a single legacy log file from May 2026 sits outside that rotation and has not been cleared yet. It is on the list.
• Feedback — until the account is deleted, or until you ask us to remove it.
• Crash reports held by Google — under Google's own retention policy, not ours.
• Anonymous totals — figures such as how many problems were solved across the whole game are kept indefinitely. They cannot be traced back to a person.

9. Deleting it

There are two routes, and they do not reach the same things. This is the same account of it that is on the support page, and it is written out here so the two never drift apart.

Ask us — this reaches everything

Email privacy@mathempire.app with the subject Delete My Data, and include either the Player Code from Settings → Your Player Code, or the email address used to sign in. A parent or guardian can send it for their child; no account with us is needed to ask. We remove:

• the account record — display name, Player Code, and the link to a Google sign-in if there was one;
• all saved progress and the mastery record;
• feedback and bug reports sent from inside the game;
• classroom membership, including the name a teacher sees and the progress attached to it;
• usage events;
• error diagnostics carrying the Player Code;
• the browser game's separate anonymous save;
• a newsletter sign-up, if an address was ever entered on this website.

We reply to confirm when it is done — within 30 days, and usually within a few days.

The button in the app — this reaches most of it

Settings → DELETE MY ACCOUNT & DATA removes the account record, the saved progress, the mastery record and in-game feedback straight away. It does not yet reach, on its own, the usage events, the classroom membership record, the error diagnostics, or — on the version currently in the Play Store — the browser game's separate save. Those we remove by hand, and we are changing the app so the button reaches all of it. If you want everything gone, email us instead.

What cannot be deleted from here

• Crash reports held by Google (Firebase Crashlytics), under Google's own policy. They record the device and the fault, not a child's name, and we cannot delete them from our side.
• Analytics already sent to Google. We can stop sending; what Google holds is governed by Google's policy.
• Purchase records held by Google Play. We never see card details. Refunds and cancellations go through Google.
• Anonymous totals that cannot be traced to a person.

Deleting the account does not cancel a subscription. Cancel that in Google Play first, or it keeps renewing.

10. Children

Math Empire is made for children, and most of its players are children. In the United States the Children's Online Privacy Protection Act (COPPA) applies to them. What we do about it:

• No advertising of any kind is shown to a player under 13, and the advertising software is never started for them.
• No sign-in is offered to a player under 13, and no email address is asked for.
• No chat, no messaging, no profiles — no way for a stranger to reach a child in the game.
• In the browser game, a player under 13 is given fixed feedback choices rather than a free-text box, so there is no open text field for a child to type personal details into.
• The birth year the app asks for stays on the device and is never sent to us.
• A parent or guardian can have everything deleted by emailing us — see section 9.

The honest exception, repeated from section 5 because it belongs here too: Google's analytics and crash reporting currently run for under-13 players as well, and excluding them is the change we are making next.

If you are a parent and you believe a child gave us something they should not have, write to privacy@mathempire.app and we will remove it.

11. Schools and teachers

The browser game at mathempire.app/play/ needs no install, no account and no email address — from a teacher or from a student. That is the version most schools use.

In the Android app a teacher can open a class and hand out a join code. When a student joins with it, the teacher sees the roster and class-level progress: who was active, problems solved, accuracy, the topics the class finds hardest. A teacher sees progress, not personal details, and there is no messaging between them. A class membership is removed when the account is deleted through the email route in section 9.

Schools that need this in writing for a review: what is collected is section 2, who processes it is section 7, how long it is kept is section 8, and the deletion route is section 9. If a district needs something the sections above do not answer, write to privacy@mathempire.app and you will get a straight answer rather than a form.

12. Reminders

The Android app can send optional reminders — a streak nudge, a milestone that is one day away. They are scheduled on the device itself: there is no push server, and no device token or notification identifier is sent to us. They are entirely optional and can be switched off in the device's own Settings.

13. Purchases

Everything bought in Math Empire goes through Google Play. We never see or store card details. Refunds and subscription cancellations are handled by Google — open play.google.com/store/account, find the order, and choose Report a problem.

14. Your rights

Depending on where you live, you may have the right to see the personal data we hold about you, to have it corrected, to have it deleted, and to receive a copy of it. To use any of those, write to privacy@mathempire.app with the Player Code or the sign-in email address. We answer within 30 days, and usually within a few days. A parent or guardian may exercise these on behalf of their child.

15. Changes to this policy

When this policy changes, the "Last updated" date at the top changes with it and the new version replaces this page. We do not currently have a way to push a notice about it into the app, so this page is the record — if you want to be certain nothing has changed, this is the place to check.

16. Contact

• Privacy and account deletion: privacy@mathempire.app
• Everything else: hello@mathempire.app
• Publisher: Rise In Rank
• Website: mathempire.app