FairFastFairFast is an intermittent fasting tracker made by Trần Văn Bình ("we").
What stays on your device
Your fasts, schedule, notes, mood, water, weight, missions, and the answers to the safety questions in setup are stored only on your device. We have no account system and no server that receives this data.
Your phone's own backup (iCloud on iPhone, Google backup on Android) may include the app's data, the same as for other apps. That backup belongs to your Apple or Google account; we cannot access it.
Home and lock screen widgets read a small summary (current fast times, glasses of water, streak) that the app shares with its widget on your device.
What we receive
We only receive the following, and none of it contains your fasting data. Photo checks are described in their own section below.
| What | Why | Provider |
|---|---|---|
| Anonymous usage events (for example "onboarding completed", "paywall viewed"), with no times, durations, goals, weights or answers | To understand which parts of the app are used | TelemetryDeck |
| Crash reports: stack trace, app version, device model and OS version. No personal information, screenshots or activity trail | To find and fix crashes | Sentry |
| Purchase status for FairFast Pro, tied to an anonymous ID | To unlock Pro on your devices and restore purchases | RevenueCat, and Apple or Google for payment |
| Counts of photo checks used and their error codes, with nothing about what a photo showed | To keep the feature working and within cost limits | TelemetryDeck |
You can turn off anonymous usage events in Settings → Share anonymous usage. We do not use advertising IDs, do not track you across apps or websites, and do not sell or share data with advertisers.
Photo checks (FairFast Pro)
"Check a meal" and "Plan from a photo" read a photo you take or pick. They only run when you start one, and never before you agree on the screen that explains them.
- What is sent: the photo, shrunk to at most 1024 pixels and with its location and other photo details (EXIF) removed, plus a fixed request asking what food or which shift times are in it. Nothing from your fasting log, schedule, weight or safety answers is sent with it.
- Who reads it: Google, through the Gemini API, acting as our service provider. Under the paid Gemini API terms, Google does not use it to train its models. Google may keep it for up to 55 days, only to detect and prevent abuse (see Google's Gemini API usage policies and terms).
- What we keep: we never receive or store the photo. The app keeps only the result on your phone: a mission you add, or the week of eating windows you apply.
- Turning it off: Settings → "Photo checks with Google Gemini" withdraws your agreement. Nothing more is sent until you agree again.
People who say in setup that they have had an eating disorder never see the meal check.
Health information
FairFast is a tracking tool. It is not a medical device and does not diagnose, treat, cure, or prevent any condition. Talk to a healthcare professional before fasting. FairFast is intended for people aged 18 and over.
Your choices
- Export: Settings → Export as CSV gives you your fasts, weight, water and missions at any time, free.
- Delete: Settings → Delete all data removes everything the app stored on your device. Uninstalling the app does the same.
- Anonymous usage events can be switched off at any time.
- Photo checks can be switched off at any time (see above).
This website
fairfast.docusmarter.com sets no cookies and runs no analytics or advertising scripts. Fonts and images are served from this site, not from third parties. Our hosting provider may keep standard server logs (such as IP address and pages requested) for security and reliability.
Changes
If this policy changes, we will update the date above and describe the change in the app's release notes.
Contact
Questions about privacy, or a request about your data: fairfast@docusmarter.com. More ways to reach us are on the contact page.