Privacy Policy

The controller responsible for personal data on guandan.online is Oscar Lin, Residency in Germany. Contact: [email protected].

Account data: email address, username, password hash, avatar, account timestamps, email-verification status, terms-acceptance status, and account settings.

Authentication and security data: refresh sessions, token metadata, user agent, IP address where stored by the server, verification codes or hashes, reset codes, and abuse-prevention records.

Game data: lobbies, seats, bot seats, match state, moves, passes, round results, game events, leaderboard-relevant data, guest-session timestamps, and technical logs needed to run and debug games.

Social and chat data: friend relationships and requests, lobby and group invitations, chat membership, read timestamps, message timestamps, and the content of global, private, group, and lobby messages.

The service processes account, social, chat, and game data to create accounts, authenticate users, connect friends, deliver messages and invitations, run lobbies and matches, maintain game history, provide support, and protect the service.

For EU users, the legal bases include performance of a contract for account, social, chat, and gameplay features, legitimate interests for security and service integrity, and legal obligations where applicable.

Chat message bodies are encrypted before database storage using authenticated AES-256-GCM encryption. Encryption keys are held by the Guandan Online server and are not stored in the message rows.

Chat is not end-to-end encrypted. The server decrypts messages to deliver them to authorized conversation members, and the operator may be technically able to access message content where necessary for operation, security, moderation, support, or legal compliance.

Lobby chats are available only to human players currently authorized for that lobby and do not appear in the main chat list. Private and group chats are limited to accounts and accepted friends or invited group members.

The app uses authentication tokens and local storage so users can stay signed in and resume sessions. These are necessary for account login and gameplay.

The service uses Umami Analytics, which sets a single cookie to distinguish unique users. This cookie does not contain personal information and is used solely for aggregate analytics.

The service does not use advertising cookies or other non-essential tracking cookies.

Hosting is provided through a netcup VPS. Email delivery is provided through Resend. DNS is provided through Cloudflare. Source-code hosting and deployment workflow use GitHub.

Analytics are provided through Umami, a privacy-focused analytics service that does not use cross-site tracking or sell data.

The service does not currently use error-tracking providers, advertising networks, or payment providers.

Some infrastructure or service providers may process data outside the European Economic Area. Where required, transfers are handled through the provider's applicable data-protection terms, adequacy decisions, or standard contractual clauses.

Guest sessions are temporary and may expire after inactivity. Account data is generally kept while the account exists.

Chat messages, friend relationships, game records, security logs, and verification records may be kept as long as needed to provide the relevant feature, operate the service, prevent abuse, resolve disputes, comply with law, and maintain game or leaderboard integrity.

Depending on where you live, you may have rights to access, correct, delete, restrict, object to, or receive a copy of your personal data.

EU users may also lodge a complaint with a competent data-protection authority. Contact [email protected] to exercise data rights.

The service does not sell personal data.