Fasting Notebook Privacy Policy

Version 1.5 · Effective date: October 31, 2026

This is a translation. If it differs from the Korean version, the Korean version prevails.

Change history: 1.5 (2026-10-31) Added a note that your device's OS backup may include the app's records · 1.4 (2026-10-30) Added a note about app lock, and added the Japanese and English versions · 1.3 (2026-10-29) Changed where app usage statistics are sent to PostHog (United States), and added transfer details and how to turn statistics off in Settings. Removed the wording about in-app purchases · 1.2 (2026-10-14) Changed app usage statistics to count by installation ID (changed analytics server) · 1.1 (2026-10-10) Added anonymous app usage statistics · 1.0 (October 2026) Initial release

Fasting Notebook has no sign-up. The fasting, weight, meal, exercise, and water records you enter, your meal and body check photos, and your profile and settings are not sent to us, the operator. We cannot receive or see these records. Only if you turn it on yourself, some records are exchanged with the health app on the same device (Apple Health or Health Connect) (section 4).

The error reporting and app usage statistics features in the app do process the information below. The app does not show advertising.

1. Information we process

Category	Information	Purpose	Retention
Records (on your device only)	Fasting times, goals, mood, and notes; weight, body fat percentage, skeletal muscle mass, and notes; meals (meal type, food, calories, nutrients, amount, and notes); exercise (type, time, distance, and calories); water (amount and type of drink); profile (sex, birth year, height, and goal weight); settings	Providing the service (records, statistics, and calorie estimates)	Your device. Deleted when you uninstall the app or use "Delete all data"
Photos (on your device only)	Photos you attach to meal and weight records (taken with the camera or chosen from your photo library)	Attaching photos to records	Storage inside the app. When you delete a record, its photo is deleted the next time the app starts. Also deleted when you uninstall the app or use "Delete all data". We do not read other photos in your library
Error information	Error details, app version, OS, and device model	Fix errors	90 days on a server in South Korea that we manage (the error reporting tool GlitchTip)
App usage statistics	Screens and features used (for example, starting or ending a fast, saving a record, or turning on reminders), app installation ID (a random number created when the app is installed), app name and version, OS type and version, device manufacturer and model, screen size, language and time zone, network type (Wi-Fi or mobile), and carrier name (on devices where it is available)	Improve the app by understanding how many people use it, popular features, and steps where people get stuck	Kept for the retention period of our analytics service, PostHog (1 year). Not linked to personally identifying information

Error information does not include the records you enter, such as notes and weight.

We count app usage statistics using a random number created when the app is installed. This is not an advertising ID or a unique device identifier. It disappears when you uninstall the app, and a new number is created when you reinstall it. The number is not shared with other apps or used for tracking (linking information from other companies' apps or websites). Statistics do not include content you type in yourself, such as weight, food names, and notes. We do not record your screen. We set up our analytics service, PostHog, so that it does not store IP addresses or infer locations from them. If you turn off Settings > Send usage stats in the app, we stop sending them from that point.

2. Sharing with third parties and outsourced processing

PostHog Inc. (United States): Analyzes app usage statistics (section 3).
We do not give your records to anyone.

3. Data stored outside your country

App usage statistics are sent to an analytics service in the United States (Article 28-8 of the Personal Information Protection Act of Korea, which sets the rules for transferring personal information abroad). Error information is sent to a server in the Republic of Korea (South Korea). If you live outside these countries, your information is transferred to them.

Item	Details
Recipient	PostHog Inc. (2261 Market Street #4008, San Francisco, CA 94114, USA · privacy@posthog.com)
Country of transfer	United States (PostHog US Cloud, Amazon Web Services data centers)
When and how	From time to time while you use the app, over an encrypted internet connection (https)
Information transferred	The "App usage statistics" items in section 1, and the IP address at the moment of sending (set up not to be stored)
Purpose	Analyzing app usage statistics (improving the app)
Retention	1 year from the day received (PostHog's retention period)
How to refuse and what happens	Turn off Settings > Send usage stats in the app. All features of the app keep working

You consent to this transfer by using the app after reading this policy and the Terms of Use.

Countries of transfer: Republic of Korea (error information), and the United States (app usage statistics).

Korean privacy law: Korea has the Personal Information Protection Act. The Personal Information Protection Commission (PIPC) supervises it. Japan's Personal Information Protection Commission publishes a report on the Korean system: https://www.ppc.go.jp/files/pdf/korea_report.pdf

How we protect your data:

The records and photos you enter are not sent to us. They stay on your device.
We keep error information on a server we manage ourselves. Only we, the operator, can access it.
App usage statistics are not linked to personally identifying information. PostHog is set up not to store IP addresses or infer locations from them. PostHog's privacy policy: https://posthog.com/privacy
Error information and app usage statistics do not include the records you enter, such as weight, food names, and notes.
We keep error information for 90 days. App usage statistics are kept for the retention period of PostHog (1 year).

4. Connecting to a health app (optional)

Only if you turn on Settings > Health app sync, the app exchanges information with Apple Health (iOS) or Health Connect (on supported devices) on the same device, within the permissions you allow. Before you turn it on, the app does not ask for permission.
Information we send: weight you recorded in Fasting Notebook, the amount of water you drank, and exercise (type, time, distance, and estimated calories burned). We do not send fasting records, meals, photos, or notes.
Information we read: when you tap "Import weight", your weight entries from the last year in the health app (for Health Connect, entries from 30 days before the day you gave permission). We do not read other health data, such as steps, sleep, or heart rate.
Information read from the health app stays in Fasting Notebook's storage on your device. We do not send it to our servers or to third parties, and we do not use it for promotion or marketing.
If you turn sync off, we stop sending from that point. Records already saved in the health app can be deleted in the health app. You can change permissions at any time in the health app (iOS: Health > Profile > Apps; Health Connect: App permissions).

5. Camera and photos

The app asks for access to the camera or photo library only when you attach a photo to a meal or weight record. It copies only the one photo you choose into the app.

6. Reminders, widgets, Live Activities, and app lock

Reminders (fasting, water, and weight) are local notifications scheduled on your device. They do not go through a server.
Widgets, lock screen widgets, and Live Activities (iOS) use only the fasting times and plan name in storage shared with the app on your device.
App lock (PIN or biometrics): Stored only in your device's secure storage. We cannot access it.

7. Backup files

When you tap "Create backup file", the app creates a file with your records and the photos attached to them, and sends it to a place you choose, such as a files app, email, or cloud storage. How the file is kept after that depends on the policy of the service you choose.
Your device's OS backup (iCloud Backup or Google account backup) may include the records and photos stored in the app. We cannot see those backups. You can turn off OS backup for the app in your device settings.

8. Your rights

Turn off app usage statistics: Turn off Settings > Send usage stats. We stop sending them from that point.
You can delete the records and photos on your device at any time under Settings > Delete all data. Uninstalling the app also deletes them.
To ask us to delete error information (kept on our server for 90 days), email fasting@hyunjins.co.kr. Tell us your app version and device model, and we will find and delete the matching records.

9. Children under 14

The Service has no sign-up, so we do not check ages. We do not recommend fasting for growing children and teenagers.

10. Do Not Track

Fasting Notebook does not respond to Do Not Track (DNT) browser signals. We do not track you across other companies' apps or websites.

11. Changes to this policy

We post the updated policy in the app and at https://fasting.hyunjins.co.kr/legal/privacy_en.html and update the effective date. For important changes, we notify you in the app.

12. Privacy officer

Hyunjins (Representative: Jang Hyunjin) · fasting@hyunjins.co.kr

Business address: 6F, 25 Hyangchon 1-gil, Gwacheon-si, Gyeonggi-do, Republic of Korea