Last updated: August 2026
Introduction
Hiyoko ("we", "our", or "the app") is committed to protecting your privacy. This Privacy Policy explains how we handle your information when you use our savings tracking app.
Data Stored on Your Device
We do not upload it, and we cannot read it.
Data kept on your device:
- Savings goals and target amounts
- Savings and expense records (amount, category, date, note)
- App settings (theme, language, currency)
- Badge data
- Chat history with your chick (including messages you type)
- Weekly review history
Data Sent to Our Server
The app talks to our server (a Cloudflare Worker) in two situations. In both, the app sends a random user ID — a UUID generated on your device the first time you launch the app. It is not linked to your name, email, Apple ID, or device identifier, and we cannot use it to identify you.
1. Subscription verification
When you subscribe, restore a purchase, or launch the app while subscribed, the app sends Apple's signed transaction receipt to our server so we can confirm the subscription is genuine. We store the following, keyed by your random user ID:
- Product ID and Apple's transaction ID
- Subscription expiry date and environment (Sandbox / Production)
Apple also notifies our server directly when a subscription renews, is cancelled, or is refunded. We do not receive or store your name, email address, or payment details.
2. AI features (Hiyoko Plus)
If you subscribe to Hiyoko Plus, the following is sent to our server and forwarded to Google's Gemini API to generate a reply:
- Messages you type to the chick, and up to the last 10 messages of the conversation for context
- Your savings context: goal name (as you typed it), target amount, current amount, progress, and remaining count
- For purchase advice: the item name and price you enter
- Your app language
It is passed through to generate the reply and then discarded. The only things we retain are the subscription record described above and a per-day request counter used for rate limiting.
Because the goal name, your messages, and item names are free text, please avoid typing anything you would not want sent to a third-party AI service.
Third-Party AI Service
We use Google's Gemini API to generate AI replies. Data sent to Google is subject to Google's privacy practices (see the Gemini API terms).
What We Do NOT Collect
- Your name, email address, or account details
- Financial account or payment card details
- Location data
- Contacts or photos
- Advertising identifiers, usage analytics, or cross-app tracking
We do not use third-party analytics or advertising SDKs. Apple may provide us with anonymous crash reports if you have enabled sharing in iOS Settings.
In-App Purchases
Subscription purchases are processed by Apple. We never see your payment information. Please refer to Apple's privacy policy for details on how they handle payment data.
Third-Party Services
- Apple StoreKit / App Store Server Notifications: subscription purchase and status
- Cloudflare Workers: hosts our server (subscription verification and the AI relay)
- Google Gemini API: generates AI replies (Plus subscribers only)
Data Deletion
- Use "Clear Data" in Settings, or uninstall the app, to delete everything stored on your device
- To have the subscription record tied to your random user ID deleted from our server, contact us via the Support page. Note that this may prevent Plus features from working until you restore your purchase
Children's Privacy
Hiyoko does not knowingly collect information from children under 13. The app is designed to be safe for all ages.
Changes to This Policy
We may update this Privacy Policy from time to time. We will notify you of any changes by updating the "Last updated" date.
Contact
If you have questions about this Privacy Policy, please visit our Support page.