Sunghyun Kim

요금메뚜기

Last updated: October 6, 2026

요금메뚜기 (“MVNO Hopper,” “the app”) reminds you before the promotional discount on your mobile plan ends and shows how much mobile data you use. This policy explains what the app collects, where it is stored, and who it is shared with.

The app is offered in Korean only and is designed for Korean carriers and budget (MVNO) plans. It is governed by the Korean Personal Information Protection Act; the Korean version of this policy prevails if the two differ. This policy covers both the iPhone (iOS) and Android apps; differences are noted where they apply.

At a glance

  • We never ask for your name, email, or phone number — not even when you sign in with Apple or Google.
  • Data usage stays on your device and is never sent to our servers.
  • Only the plan details you enter are stored on our server, and they are deleted as soon as you delete your account.
  • We use Google services for usage analytics and ads. On iPhone, personalized ads are shown only if you allow tracking; on Android, they follow your device’s advertising ID settings.

1. Information we collect and why

Account

  • What: a randomly generated account ID, your sign-in methods (anonymous, Apple, Google — anonymous and Google on Android) and their identifiers, and sign-up / last sign-in times.
  • Why: to store your plans in your account and restore them on a new device or after reinstalling.

Plan details

  • What: carrier, plan nickname, activation date, discount end date, monthly fee and fee after discount, data / call / text allowances, throttled speed, billing day, and cancellation date.
  • Why: discount-end reminders, showing fees and allowances, and allowance alerts. We never ask for your phone number or sign in to your carrier account.

Push token (iPhone app)

  • What: a Firebase Cloud Messaging registration token.
  • Why: when usage tracking is on, the app receives a silent, content-free signal about every 10 minutes so it can measure usage while closed. The same signal goes to every user and is never shown.
  • The Android app measures usage with a scheduled background task about every 15 minutes instead, and does not receive a push token.

Analytics

  • What: in-app actions (e.g. completing plan setup steps, editing or cancelling a plan, notification permission result, where the purchase screen was opened, purchases and refunds), carrier and plan type, bucketed counts of plans / widgets / SIMs, device model, OS and app version, approximate region, and an app instance ID.
  • Why: to learn which features are used and where people get stuck.
  • Never sent: your account ID, plan nickname or custom carrier name, fee amounts, dates, or data usage.

Crash and error reports

  • What: a record of the crash or error (code location and the app’s recent activity log), device model, OS and app version, a random per-install ID, and your account ID.
  • Why: to find and fix crashes and errors. The account ID lets us find your reports when you contact us (support emails include the same ID). Reports don’t include plan details or data usage — values in error logs are masked.

Advertising

  • What: the advertising identifier (on iPhone, the IDFA — only if you allow tracking; on Android, the advertising ID), ad impressions and clicks, device information, and approximate location inferred from your IP address.
  • Why: to show ads that keep the app free and to measure them. On iPhone, if you don’t allow tracking, you see non-personalized ads. On Android, you can reset or delete your advertising ID in your device’s ad settings (Settings → Privacy → Ads, or Settings → Google → Ads); once deleted, you see non-personalized ads. Every feature still works either way. With Pro, no ads are requested.

Purchases

Apple (iPhone) or Google Play (Android) processes payments; we never see your payment details. Product, price, currency, and refund status are included in analytics for revenue reporting.

2. Stored only on your device

  • Data usage: cellular traffic totals read periodically from the operating system (iOS or Android), recorded by date, hour, and SIM, plus any usage you enter manually. The app cannot see which apps or sites you used, or the content of calls and messages.
  • SIM links, settings, and a copy of your plans for the widget and notifications.

These are deleted when you delete the app.

3. Permissions

  • Notifications: discount-end reminders (scheduled locally on your device) and data allowance alerts.
  • Calendar: no calendar permission is requested. “Add to Calendar” opens the system (iOS or Android) event editor and you save the event yourself; the app never reads your calendar.
  • App Tracking Transparency (iPhone): used only for personalized ads, as described above.
  • Advertising ID (Android): granted automatically at install and used for ads and analytics as described above. Notifications are the only permission the Android app asks for.

4. Service providers and international transfer

We do not sell your information. We use these providers, which may process data outside Korea:

  • Google LLC (USA) — Firebase Authentication, Cloud Firestore (plan details stored in the Seoul region), Cloud Functions, Cloud Messaging and Remote Config (iPhone app), Google Analytics for Firebase, Firebase Crashlytics, Google AdMob, and Google Play Billing (Android in-app purchases). See the Google Privacy Policy and how Google uses information from partner apps.
  • Apple Inc. (USA) — Sign in with Apple, in-app purchases, and push notification delivery (iPhone app).

5. Retention

  • Account and plan details: until you delete your account, then deleted immediately.
  • Analytics: deleted automatically after the Google Analytics retention period (up to 14 months).
  • Crash and error reports: deleted automatically after 90 days.
  • Advertising data: per Google’s retention policies.
  • On-device data: until you delete the app.

6. Your choices

  • View and edit your plans in the app at any time.
  • Delete your account in Settings → Delete Account (“Delete Data” for anonymous users). If you pick a reason when deleting (optional), only the selected reasons are sent to analytics.
  • Turn off usage tracking in Settings. On iPhone, turn off tracking in iOS Settings; on Android, reset or delete your advertising ID in your device’s ad settings. Notifications can be turned off in your device settings.
  • Anonymous accounts cannot be recovered after signing out or deleting the app. Contact us if you want the data left on our server deleted.

7. Children

The app is not directed at children under 14 and does not knowingly collect their information. If we learn that we have, we will delete it promptly.

8. Security

All data is sent over encrypted connections (TLS), and security rules restrict plan details to your own account.

9. Contact

Privacy officer: Sunghyun Kim (developer) — support@sunghyunkim.com

10. Changes

We will post changes on this page and update the “Last updated” date above.