Privacy Policy

1. Who is responsible and how to contact us

Data controller: YU-CHIUAN LIU (Yuken Studio / GuGuFin). For questions or requests about this policy or personal data, email yuken.studio@gmail.com.

2. Ledgers and bookkeeping data

Ledgers, accounts, income, expenses, assets, liabilities, investments, categories, and notes you enter are primarily stored on your device. You do not need a GuGuFin account to use the app. Using local bookkeeping does not upload your complete ledger to a GuGuFin-operated central accounting server.

If you enable Apple iCloud sync or sharing for a ledger, its data is transmitted to and stored in your iCloud account space through Apple CloudKit, and may be made available to members you invite. Apple’s own terms and privacy policy govern its handling of its services.

3. Analytics and crash diagnostics

The app uses Firebase Analytics to understand feature usage and Firebase Crashlytics to receive technical diagnostics about crashes and unhandled errors. These data may include app version, device and operating-system information, feature interaction events, error messages, and stack information.

Analytics event parameters are restricted. The app is designed not to send account balances, ledger names, bookkeeping text, dates, currencies, or local bookkeeping identifiers as analytics parameters. Crash diagnostics may contain technical context from the time an error occurred, so please do not include unnecessary personal or financial information in error messages or support reports. Google/Firebase processes these data under its service terms.

The in-app Export Diagnostics file is created on your device. A recipient receives it only if you export and send it to support or another person.

4. Exchange rates and market-data requests

To provide reference exchange rates and market data for stocks, funds, cryptocurrency, or precious metals, the app requests relevant currency codes, product symbols, or market identifiers from Supabase data services. These requests retrieve market data; they do not send your account balances or complete transaction history as query content. Providers may record technical connection data needed to operate their services.

5. macOS MCP and AI clients

The macOS MCP Server runs locally on your Mac and provides queries or proposed actions for the ledger currently loaded there. An MCP client you choose can receive the data you ask it to query. If that client uses cloud AI, the data may then be processed by that AI provider. Retention, use, and deletion are governed by the client and AI provider you choose, not by GuGuFin.

6. Backups

You can create a backup encrypted with a password you choose. You export the backup yourself and choose where to store it. If you place it in iCloud Drive, another cloud drive, messaging, or another service, that provider’s policy applies. GuGuFin does not store exported backup files for you. Keep your password safe; without it, the backup may not be recoverable.

7. Website browsing information

The website uses Google Analytics to understand page visits and website usage. Google Analytics may process pages viewed, referral information, browser and device details, and identifiers or similar technologies used for analytics. The website also stores your language preference in your browser’s local storage for your next visit.

The website is hosted by Firebase Hosting. Google’s hosting infrastructure may process technical connection data needed to operate, secure, and troubleshoot the service. When you follow App Store, Google Play, social, or support links, those services handle data under their own policies.

8. Service providers and data locations

Depending on the features you use, data may be processed by Apple (CloudKit and iCloud), Google (Firebase Analytics, Crashlytics, Analytics, and Hosting), or Supabase. These providers may process data on servers outside your country or region under their service terms and privacy policies. GuGuFin does not sell your ledger data.

9. Retention and deletion

Local ledger data remains on your device until you delete it in the app or on your device. Exported backups remain in the location you selected until you delete them. You manage iCloud ledger and sharing data through the app, your Apple account, and sharing settings.

Analytics and crash-diagnostic data are retained according to Firebase project settings and Google/Firebase policies. Support messages are retained as needed to handle your request and meet necessary recordkeeping obligations.

10. Your choices and privacy rights

You decide what bookkeeping information to enter and whether to enable iCloud sync or sharing for each ledger. The app’s local bookkeeping works without iCloud, but other devices will not receive that ledger through iCloud.

Depending on applicable law, you may request access to, a copy of, correction to, or deletion of personal data we hold, or ask us to stop collecting, processing, or using it. Email yuken.studio@gmail.com with your request. We may need to verify your identity to protect the data. For data held directly by Apple, Google, Supabase, or an AI client you chose, submit the request through that provider.

11. Policy updates

We may update this policy when app features, service providers, or applicable requirements change. The updated effective date will appear on this page.