Armchair Sudoku

Privacy policy

Last updated 13 October 2026.

Armchair Sudoku is made by Pikeworks, a sole trader in Northern Ireland. This is what the app keeps, what leaves your phone, and why.

What stays on your phone

Your puzzles, games in progress, settings, profiles, statistics and achievements are kept in the app's private storage on your phone. There's no Armchair Sudoku account and no Armchair Sudoku server, so none of it is sent to me. Puzzles are made on the phone, and the daily puzzle is worked out from the date.

A backup file or a CSV export is only made when you tap to make one, and it goes wherever you choose to send it.

Puzzles from paper

If you use A puzzle from paper, the app reads one photo: one you take with your phone's camera when you tap Take a photo, or one you choose with your phone's own photo picker. It is read on your phone, to find the puzzle's numbers, and it is never sent anywhere: not to me, and not to anyone else. No copy of the photo is kept once it has been read. The puzzle it found is kept like any other, so you can carry on with it.

Adverts

Armchair Sudoku shows adverts from Google AdMob, through the Google Mobile Ads SDK, on Android and on iPhone. A small banner can sit along the top of the screen, above the puzzle board, and a full screen advert never appears during a puzzle. To show and measure adverts, and to prevent fraud, Google receives information from your phone that can include:

• your IP address, from which a rough location can be worked out;
• your phone's advertising ID (on an iPhone, only if you allow tracking, see below) and an app set ID or identifier for vendors;
• device details such as the model, operating system and language;
• which adverts were shown and tapped;
• diagnostic information about how the adverts loaded.

In the UK, the European Economic Area and Switzerland, Armchair Sudoku asks through Google's consent message whether adverts may be personalised before any are requested. In US states with their own privacy laws you can opt out of the sale or sharing of your information. Either way you can change your answer at any time under Settings, Privacy choices. If you say no, you still see adverts, but they aren't personalised.

On an iPhone, Apple also asks whether Armchair Sudoku may track your activity across other companies' apps and websites. If you allow it, Google may use your iPhone's advertising identifier to personalise adverts. If you ask the app not to track, the identifier is never shared, and adverts are chosen without it. Armchair Sudoku works the same whichever you choose, and you can change your mind in the iPhone's Settings, under Privacy & Security, Tracking.

On Android you can reset or delete your advertising ID in your phone's settings, under Google, Ads. How Google uses this information is explained at policies.google.com/technologies/partner-sites.

If you buy Sudoku Complete or Remove adverts, the app stops asking for adverts.

Feedback you send

If you write to me from the "Tell me what you think" box in Settings, what you type is sent to the Pikeworks server along with the app version, whether you are on Android or iPhone, and the model of phone, so I do not have to ask. You can also add a screenshot from your phone with "Add a screenshot". Only the one picture you choose is read, through your phone's own photo picker, and it is sent as a fresh copy at most 1280 pixels tall, with nothing the phone stored in the file (such as where or when it was taken) going with it. That is all that goes: no account, no identifier, and nothing else from the app.

Test versions of the app, the ones given to testers before a release, also have a strip across the top of every screen for reporting a problem. It sends the same things, plus a picture of the app's own screen as it was when you tapped the strip, and which part of the app you were in (for example the board, and the puzzle's number). The picture shows only the app, never anything else on your phone, and you can switch it off before sending. The versions on Google Play and the App Store for everyone have no strip.

The email address is optional and is only there so I can write back. If you leave it out I have no way of knowing who sent it. It goes to the Pikeworks feedback service, which runs on Cloudflare and keeps what you send in the European Union; Cloudflare is a company in the United States. Your IP address is used to stop abuse and is never stored. A copy of the message, and of the picture if there is one, is posted to a private Discord channel that only I can read, so I see it on my phone straight away; Discord is a company in the United States. Feedback is kept until it has been dealt with, and deleted within six months after that, picture and Discord copy included. You can ask for yours to be deleted sooner using the address below.

Purchases

Sudoku Complete and Just remove adverts are one-off purchases through Google Play or the App Store. RevenueCat checks the purchase. It receives an anonymous app user ID and the purchase receipt, so it can confirm what you bought and restore it on another phone. I never see your name, email address or payment details. RevenueCat's policy is at revenuecat.com/privacy.

Permissions

Armchair Sudoku only uses the internet for adverts and purchases. It doesn't ask for your location, contacts or microphone. The camera is only used when you tap Take a photo: on Android your phone's own camera app takes the picture, so no permission is asked, and an iPhone asks you once. Photos are only ever the one you take or choose, as above.

Children

Armchair Sudoku is meant for adults and isn't aimed at children.

Deleting your information

Uninstalling Armchair Sudoku deletes everything it stored on your phone. I don't hold a copy. For what Google holds about adverts, reset or delete your advertising ID on Android, or turn tracking off for the app on an iPhone, and use the controls in your Google account.

Your rights

Armchair Sudoku has no account and no server of mine, so there is nothing here for me to look up, correct or hand over: everything the app keeps is on your phone, where you can read it and delete it yourself. Where an advert or a purchase means something goes to Google or to RevenueCat, their own policies and controls cover it, and your phone's own settings let you reset or delete the advertising ID on Android or stop tracking on an iPhone.

Under UK GDPR you can still ask for a copy of what is held about you, ask for it to be corrected or deleted, object to it being used for personalised adverts, and complain to the Information Commissioner's Office at ico.org.uk. Personalised adverts rely on the consent you give through Google's message, and you can change that answer at any time in Settings under Privacy choices.

Changes

If this policy changes, the date at the top changes and the new version replaces this one.

Contact

Email me at armchairsudoku@pikeworks.co.uk.