Privacy and your saved progress.

This guide explains the data used by the MineChess game features. For privacy questions or account requests, contact hello@minechess.app.

Playing as a guest

You can play computer games, use lessons and solve puzzles without creating an account. MineChess stores your game preferences, nickname if supplied, recent unfinished games and completed activities in your browser’s local storage. These records make it possible to return to your game. Solo hint steps, undo usage and unfinished puzzle attempts are also saved locally, so reloading does not lose learning progress. Hint usage records are used to describe supported or independent practice, not to impose a daily allowance.

Clearing browser storage, using a different browser or changing devices can remove access to local progress. Export a copy from Settings before clearing it. Shared devices may expose locally saved information to other people using the same browser.

Optional accounts and cloud activities

Signing in is optional. Authentication is provided through the Base44 platform. When you sign in and choose to keep your guest progress, completed game, puzzle and lesson activities are merged into your account and synced to the application database. Your chosen pieces, settings and unfinished sessions are preserved with the account on this browser, but are not currently synchronised to other devices. Guest-to-account transfer keeps a local recovery copy until completed activities have successfully synced. If older guest progress is still present after signing in, the Progress page asks you to confirm ownership before adding it. Game activities include move history, results, dates and opponent nicknames where relevant.

Activities are displayed privately to their account owner. They are not public profiles or leaderboard entries. The application operator and hosting provider may access data as needed to operate, secure and support the service. This is not an end-to-end encrypted storage service.

Private friend games

Online rooms store nicknames, chosen piece sets, move history, room status and invitation information. Your browser holds a random private player key; the server stores a hash of that key. Shared invitation links do not contain the private player key. A signed-in player may explicitly link an existing guest seat using “Save to my account”. The room then stores that account’s user ID for the relevant side, so the same signed-in account can retrieve and play that game on another browser without exporting a private player key. The other player’s seat is not linked by that action.

Share an invitation only with your intended opponent. Someone holding an unused invitation may be able to take its available seat. New unused invitations remain available for seven days. Joined games become read-only after 30 days without a confirmed move, and completed rounds allow rematches for 90 days. These are gameplay limits, not automatic deletion of database records. When a rematch is accepted, completed-round move records and results are retained for later review. Private game boards remain accessible for review to a player with the correct credentials while their records exist.

Completed-game review

After a game finishes, a Stockfish browser worker can analyse its positions locally on your device. Recent analysis results may be cached in browser storage to avoid repeating the same work. Engine evaluations are estimates, not official ratings or guaranteed results. The review cache is separate from saved game progress, and review controls do not provide live assistance during an online friend game.

Usage measurement and hosting

The optional “Share product usage events” setting is off by default in this version. Turning it on allows gameplay milestones, such as starting or completing a game, to be sent to the Base44 analytics service. These custom events exclude nicknames, move histories and invitation codes. The provider may associate requests with its own session or account information.

Hosting and authentication can still create operational records such as network, device, security and access logs. Turning off optional custom events does not switch off hosting operations or records maintained by the hosting provider.

Optional emails and Resend

You can choose private-game updates, daily or weekly puzzles, a weekly activity summary and occasional milestones in Settings. These recurring emails are off unless you select them and confirm your email address. We store your email choices, confirmation dates, time zone and delivery records, and use Resend to send the messages.

A friend may send an invitation they have asked you to receive. Receiving an invitation does not put you on a mailing list. You can stop optional emails from their footer without signing in. Delivery failures, complaints and recipient opt-outs may prevent further sends. Account authentication and password-reset messages are managed separately by Base44.

Private game emails include a signed, time-limited link that can restore your playing seat on another device. It is not the raw player key, but anyone with that private link may be able to use your seat until it expires. Do not forward these emails. Email preference links are also private. Use the separate public sharing page or create a new invitation to bring a friend.

Queued reminders are checked against your current preferences and the latest game state before sending. Game reminders have quiet hours and frequency limits. Delivery records are available to platform administrators; they are not public profiles. No contact address book is uploaded by sharing a link.

Turn reminders and device notifications

“Tell me when it’s my turn” lets you choose email reminders for an individual game. Requesting a private recovery email does not automatically enrol that game in reminders. Turning off its reminders does not disable the recovery link or change your puzzle and newsletter choices.

Where device notifications are available and activated, enabling them requires your explicit choice and browser permission. We store the browser’s push subscription, a hashed device identifier, the linked room and playing side, consent time, time zone and limited notification records. Only authorised server operations and platform administrators can access these records. Your raw private playing key is not stored in a push subscription.

Device notifications show a general MineChess reminder, not player names or move details. Tapping one opens a board that still requires your playing credentials. The notification service worker does not cache game pages or API responses. You can stop one game’s device alerts in its reminder panel or stop all alerts on this browser from Settings. Email and device alerts are separate choices. When device push has not been activated, the interface says so and does not request browser permission.

Younger players and shared devices

Use a nickname instead of a full name. Do not share personal details, passwords or private player keys. Friend games do not have open chat or a public player directory. A parent or guardian should help younger players decide whether to create an account or share an invitation.

Managing your information

Settings lets you export locally available completed activities and clear progress on the current device. Clearing local data does not remove cloud activities or delete an account. Cloud activities may return when the account next syncs.

For access, correction, deletion or other privacy-related requests, email hello@minechess.app using the address associated with the account where possible. Do not attach passwords or private player keys. The team may need to verify ownership before acting on a request.

Contact and support information explains what to include when reporting a problem.