Privacy Policy for LeanLine
Last Updated: May 21, 2026
1. Introduction
Welcome to LeanLine. This Privacy Policy explains how LeanLine collects, uses, shares, stores, and protects information when you use our mobile application. By using LeanLine, you agree to the collection and use of information in accordance with this policy.
LeanLine is operated by Minjian Hu, an individual developer. For privacy requests, questions, complaints, or claims, contact us at LeanLine@163.com.
2. Data We Collect
LeanLine is designed with privacy in mind. We do not require you to create an account with an email address, phone number, or real name. We collect the following data to make the app function:
- App-Specific Identifiers: We generate a random app-specific identifier that does not require your email address, phone number, or real name. This identifier is used to operate your account, sync app data, manage subscriptions, connect you with friends, challenges, and Squads, support safety features, and respond to account or support requests.
- Profile and Social Data: You may optionally provide a nickname and an avatar photo. Users you accept as friends may see your nickname, avatar, current streak days, and other social profile details shown in the app. If you join or create a Squad, other members of that Squad may see your nickname, avatar, Squad role, Pro badge status, Squad reactions, relative progress, leaderboard position, and cycle results. If you engage in a challenge with a friend, that friend may see your relative challenge progress. By joining a challenge or Squad, you choose to share relative progress or logging activity with the other participants in that challenge or Squad. You can avoid this sharing by not joining social features. Because LeanLine allows users to view this data, we cannot control the actions of other users, such as taking screenshots, saving shared cards, or forwarding invite codes. We strongly recommend only accepting friend and challenge requests from people you trust, and only joining or sharing Squad codes with people you trust.
- Fitness Data (Local-First Weight Privacy): Your absolute weight data never leaves your device. LeanLine stores your raw weight logs strictly locally and, if you enable Apple Health, within your iOS Apple Health app. To power social challenges and Squads, LeanLine uses privacy-preserving calculations: our servers may receive and process relative progress, such as “lost 2 lbs,” “gained 1 kg,” or “lost 1.5%,” or logging activity, such as the number of days or times you logged weight, to calculate scores, leaderboards, and cycle results. We never upload, collect, or store your actual body weight on our cloud servers. Please note that relative progress can still reveal weight trends, so you should only share social progress with people you trust.
- Squad Invite Codes and Shared Spaces: Squads can be joined using invite codes. Anyone who receives a valid invite code may be able to join the Squad until the Squad is full or the code is no longer valid. If you create or share a Squad invite code, you are responsible for sharing it only with people you want to participate with.
- Siri & System Integrations: LeanLine supports iOS system integrations, such as Siri and Apple Shortcuts. Any health data submitted through these Apple services is protected and handled according to this Privacy Policy.
- Photos and Camera Access: When you choose to upload a profile avatar, upload a Squad background image, or save a generated Share Studio card to your device, we will request access to your photo library where required by iOS. We only access the specific photo you actively select, and we only write images to your library when you explicitly use the app’s sharing or exporting features. Uploaded avatars and Squad background images may be visible to the friends or Squad members who can view the relevant profile or Squad, and may be stored using publicly accessible image URLs. We do not scan your photo library in the background, nor do we upload any unselected photos to our servers.
- Device Information and Push Notifications: To send you timely updates regarding friend requests, challenge nudges, Squad activity, reactions, and daily reminders, we collect your device’s anonymous Push Notification Token (APNs) and basic device model/OS version. We use OneSignal, a third-party notification service, to manage and deliver these notifications. OneSignal receives the information required to facilitate this service. We do not collect invasive tracking identifiers such as IMEI, MAC addresses, or GPS location data. You can manage or disable push notifications at any time in your iOS Settings.
- Reports, Blocks, and Safety Records: If you report a user or Squad, block another user, or otherwise contact us about safety concerns, we may store the information needed to review the report, enforce our Terms, prevent abuse, and protect users.
3. Optional Apple HealthKit Integration
As an optional feature, you may choose to connect LeanLine with Apple Health. LeanLine is fully functional without this connection. If you explicitly choose to enable this feature, LeanLine will request read and write access to your Apple Health data, specifically Body Mass.
- If you grant permission, HealthKit data is used exclusively to import your past weight history into LeanLine and to sync your new weight logs back to your device’s Apple Health app.
- We do not use Apple HealthKit data for marketing, advertising, or any other commercial use cases.
- We do not sell, share, or transfer your Apple HealthKit data to any third parties.
- You can manage or revoke LeanLine’s access to Apple Health at any time via your iOS Settings. Revoking access will not prevent you from using the core features of LeanLine.
We use the information described in this policy to:
- operate and improve LeanLine;
- sync your app account and social features;
- calculate challenge and Squad scores using relative progress or logging activity;
- display friends, challenges, Squads, leaderboards, reactions, and Share Studio cards;
- process purchases and manage LeanLine PRO access;
- send notifications you enable or allow;
- respond to support, privacy, and safety requests;
- detect, prevent, and respond to abuse, fraud, technical issues, and violations of our Terms.
We do not sell your personal information. We do not use your HealthKit data, raw weight logs, or relative weight progress for advertising.
5. Data Storage and Third-Party Services
We use Supabase, a third-party backend provider, to store and process the server-side data needed to operate LeanLine, including your app-specific identifier, profile, avatar URL, Squad background URLs, friend relationships, Squad membership, relative weight change records, challenge data, Squad data, reports, blocks, and other data needed to operate LeanLine’s social features.
We use Apple for the secure processing of in-app purchases and subscriptions. To manage and validate these subscriptions, we use RevenueCat, a third-party subscription backend. RevenueCat processes purchase receipts from Apple to unlock your LeanLine PRO features, but they do not have access to your payment details, Apple ID, or personal identity. We never store or process your payment information on our own servers.
We use OneSignal to manage and deliver push notifications. OneSignal receives the information needed to send notifications, such as push tokens and basic device information.
6. Data Retention
We retain account and social data for as long as needed to provide LeanLine, comply with law, resolve disputes, enforce our Terms, prevent abuse, maintain security, and support legitimate business operations. Retention periods may vary depending on the type of data and why it is used.
7. User Rights and Data Deletion (GDPR & CCPA Compliance)
You own your data. You have the right to access, modify, or delete your data, subject to applicable law. You can request deletion of your LeanLine account directly within the app by navigating to Settings and selecting “Delete Account.”
When you delete your account, LeanLine will delete or anonymize the data associated with your app-specific identifier, including your profile, avatar, friend relationships, active challenge participation, Squad membership, and server-side social records where deletion is technically and legally possible. Your local weight history can also be removed from your device through the app. Some information may remain for a limited period in backups, logs, safety reports, fraud-prevention records, legal compliance records, or content that other users have already viewed, saved, screenshotted, or shared outside LeanLine. Completed challenge or Squad results may be retained in anonymized or historical form where needed to preserve the integrity of other users’ records.
8. Children’s Privacy
LeanLine is not intended for children below the minimum age required to use digital services or provide valid consent in their country or region. If you are below the applicable minimum age, please do not use LeanLine or provide any information through the app without appropriate parent or guardian consent. If we learn that we have collected personal information from a child without the required consent, we will take reasonable steps to delete it.
If you have any questions about this Privacy Policy, please contact us at: LeanLine@163.com.