Privacy Policy

Who we are

Sudoku Samurai (“Sudoku Samurai”, “we”, “us”) is an independent game developed and published by Lucas Howlett. The mobile app is distributed on the Apple App Store and Google Play under the bundle identifiers com.lucashowlett.sudoku-samurai (iOS) and com.lucashowlett.sudoku_samurai (Android). The website is published at https://sudoku-samurai.app.

You can reach us at lucas@lucashowlett.com for any privacy question, request, or complaint.

The short version

• We do not require an account. The app does not ask for your name, email, phone number, or any other contact information.
• Your puzzle progress, settings, statistics, and best times are stored locally on your device. We do not back them up to a server.
• We do not sell your personal information, and we do not show third-party advertising in the app.
• In-app purchases are processed by Apple, Google, and our receipt-validation provider RevenueCat. We do not see or store your payment card details.
• We use a small amount of anonymous analytics to understand aggregate app and site usage and to fix crashes.

Information we collect

Information you give us directly

The app does not require you to create an account or to provide any personal information to play. If you contact us by email, we will receive whatever you choose to write to us, along with your email address, so that we can reply.

Game data stored on your device

The app saves the following information locally on your device using your operating system’s standard storage (Async Storage and MMKV). This data does not leave your device unless your device or operating system backs it up to its own cloud service (for example, iCloud or Google’s backup):

• Saved puzzles and their current state.
• Game preferences and accessibility settings (theme, sound, haptics, autocandidates, wrong-placement behaviour, and so on).
• Personal statistics, including completed puzzles, best times, and campaign progression across the warrior ranks.
• The status of in-app purchases and the daily puzzle.

You can clear this data at any time by deleting the app, or by using the “Reset progress” or equivalent options in the app’s settings where available.

Purchase information

When you make an in-app purchase, the transaction is handled by Apple (App Store) or Google (Google Play). They charge your account using the payment method on file with them. We never see your full payment card number, security code, or login credentials.

To validate purchases and to allow you to restore them on a new device, we use RevenueCat, a service that acts as our processor for receipt validation. RevenueCat receives:

• A randomly generated identifier for your install (a RevenueCat anonymous user ID, prefixed with $RCAnonymousID:). This identifier is not your name or email.
• The purchase receipt issued by Apple or Google, the product purchased, the country of purchase, and the entitlement status.
• Basic device and platform information used to associate receipts with the correct platform.

Apple and Google may also share standard purchase metadata with us through their developer reports (for example, country and aggregated revenue). We do not receive your name, address, or card details from them.

Analytics and diagnostics

We use Expo Insights in the mobile app to collect aggregate metrics such as app version, platform, country, session counts, and crash signals. These metrics use a randomly generated install identifier and do not contain your name, email, phone number, or precise location.

On the website we use Vercel Analytics, which is cookieless and uses a hashed daily identifier to estimate unique visitors. Where it is configured, we also use Google Analytics to understand which pages are read. You can opt out of Google Analytics by enabling your browser’s Do Not Track or Global Privacy Control signal, by using a content blocker, or by installing the Google Analytics opt-out add-on.

Notifications

The app uses Expo Notifications to deliver optional reminders such as the daily puzzle. You will be asked for permission before any notification is sent, and you can withdraw permission at any time in your device settings.

Reviews

We may occasionally show the system “rate this app” prompt provided by Apple or Google. This prompt is rendered by the operating system. Any rating or review you submit is sent directly to the App Store or Google Play and is governed by their respective privacy policies.

How we use information

• To run the game on your device and save your progress.
• To process and restore in-app purchases and to confirm that you are entitled to features you have unlocked.
• To understand, in aggregate, how the app and website are used, so we can fix bugs and prioritise improvements.
• To respond to you when you contact us.
• To comply with our legal obligations, for example to keep tax records of purchases as required by law.

We do not use your information for behavioural advertising and we do not sell or rent personal information to third parties.

Legal bases (UK and EU users)

If you are in the United Kingdom or the European Economic Area, we rely on the following legal bases under the UK GDPR and the EU GDPR:

• Performance of a contract — to deliver the game, process and restore in-app purchases, and provide customer support you request.
• Legitimate interests — to keep the app secure, prevent abuse, and understand aggregate usage and crash data so we can improve the product. We balance these interests against your right to privacy.
• Consent — for optional notifications and, where required, for non-essential analytics cookies on the website. You can withdraw consent at any time.
• Legal obligation — for example, retaining purchase records for tax purposes.

Sharing your information

We share information only with the following parties:

• Apple and Google — for app distribution, notifications, in-app purchase processing, and crash reports you choose to share with the platform.
• RevenueCat — to validate and restore in-app purchases.
• Expo (Expo Insights) and Vercel — to host the website and to receive aggregated analytics and diagnostic data.
• Google Analytics — where it is configured on the website, to understand site usage.
• Professional advisers and authorities — where we are required to disclose information by law, court order, or to protect our legal rights.

International transfers

Our service providers may process information in countries other than the one you live in, including the United States. Where we transfer personal information out of the UK or the EEA, we rely on the appropriate safeguards offered by the provider, such as the EU Standard Contractual Clauses or the UK International Data Transfer Addendum.

How long we keep information

• Game data on your device is kept until you delete it or uninstall the app.
• Purchase receipts and entitlement records are retained for as long as you may want to restore your purchase, and as long as tax and accounting law require (typically up to seven years).
• Aggregated analytics are kept for the retention period set by the relevant provider.
• Email correspondence is kept for as long as needed to handle your request and any follow-up.

Children

Sudoku Samurai is suitable for general audiences. We do not knowingly collect personal information from children under 13 (or under 16 in jurisdictions where that is the relevant age). If you believe a child has provided us with personal information, contact us at lucas@lucashowlett.com and we will delete it.

Your rights

Depending on where you live, you may have the right to access, correct, delete, restrict, or object to the processing of your personal information, and to receive a copy of it in a portable form. UK and EU residents have these rights under the UK GDPR and EU GDPR. Residents of California and other US states with comprehensive privacy laws have analogous rights, including the right to opt out of the “sale” or “sharing” of personal information for cross-context behavioural advertising. We do not engage in such sales or sharing.

To exercise any of these rights, email lucas@lucashowlett.com. Because we do not store the bulk of your game data on our servers, the most effective way to delete your information is to uninstall the app, which removes it from your device. UK and EU users also have the right to lodge a complaint with their local data protection authority, for example the UK Information Commissioner’s Office (ICO).

Security

We use industry-standard measures to protect the limited information we hold, including encrypted connections (HTTPS), access controls on our service providers’ dashboards, and the security features built into the iOS and Android platforms. No system is perfectly secure, and we cannot guarantee absolute security.

Changes to this policy

We will update this page when our practices change. The “Last updated” date at the top reflects the most recent revision. If we make a material change, we will provide additional notice in the app or on the site before the change takes effect.

Contact

Questions, requests, or complaints can be sent to lucas@lucashowlett.com. Please include enough information to help us understand and respond to your request. See also our Terms of Use.