Last updated: July 8, 2026
LeanFast ("the App") is developed by VertexLab Solutions. We are committed to protecting your privacy. This policy explains how we handle your data.
The data you enter into LeanFast (weight, fasting sessions, food logs, progress photos, water intake) is stored on your device. We do not sell your data or use it for advertising. The one exception is the optional AI Coach feature, which transmits limited data to generate responses — see the "AI Coach" section below.
App data is stored locally on your device using Apple's SwiftData framework. Except for the optional AI Coach feature described below, no data is sent to any server, and we do not have access to it.
LeanFast may optionally integrate with Apple HealthKit to read and write weight data. This data is governed by Apple's HealthKit privacy policies and is never shared with third parties. HealthKit access is entirely optional and requires your explicit permission.
LeanFast does not use any analytics SDKs, tracking pixels, or advertising frameworks. We do not track your behavior or usage patterns.
LeanFast uses Apple's StoreKit 2 for in-app purchases. Purchase transactions are handled entirely by Apple and are subject to Apple's privacy policy.
The optional AI Coach is powered by Cloudflare, Inc. (which hosts our backend proxy service) and Anthropic, PBC (which provides the Claude AI model). Data sent to the AI Coach is handled as described below and is subject to these providers' respective privacy policies.
On-device features such as weight prediction and pattern analysis run entirely on your device. The AI Coach chat is an optional feature that sends data off your device. When you send a message to the coach, your message, recent coach chat history, and a summary of your fasting context (which may include your goal, fasting plan, experience level, current and target weight, streak, number of completed fasts, completion rate, and recent weight change) are transmitted over an encrypted connection to our backend service hosted on Cloudflare, which forwards it to Anthropic to generate a reply using the Claude AI model.
This data is used solely to produce your coaching response. It is not used to train AI models, is not sold, and is not used for advertising. We do not retain your chat content on our servers beyond what is needed to process each request. If you do not use the AI Coach, none of this data leaves your device.
LeanFast is not intended for children under 17. We do not knowingly collect data from children.
LeanFast does not provide medical advice. The app is intended for general wellness purposes only. Consult a healthcare professional before starting any fasting program.
We may update this policy from time to time. Changes will be posted on this page with an updated date.
If you have questions about this privacy policy, contact us at: tuhin014@gmail.com
© 2026 VertexLab Solutions. All rights reserved.