Just Fast vs Fastly
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Just Fast
This app tracks both your fasting periods and your eating windows, offering a unique dual-countdown feature. It visualizes metabolic phases like fat burning and ketosis, supports various fasting methods, and provides insights into your progress. It's designed to be user-friendly and privacy-conscious, working entirely offline.
- Eating window countdown
- Fasting phases visualization
- Support for multiple fasting methods
- Streak tracking with grace periods
- Pattern insights
- Weight and BMI tracking
- Smart notifications
- 100% offline functionality
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Just Fast is the intermittent fasting timer that tracks both your fast and your eating window — a combination no other fasting app offers. Whether you're new to 16:8 or pushing into 20:4, OMAD, or custom schedules, Just Fast gives you a clear, distraction-free timer alongside the insights to understand what your body is doing and build habits that stick. EATING WINDOW COUNTDOWN — ONLY IN JUST FAST Most fasting apps tell you when your fast ends. Just Fast also tells you when your eating window closes. Know exactly how much time you have left to eat, so you stop overrunning your window by accident. KEY FEATURES • Eating Window Countdown — track when your eating window closes, not just when your fast ends • Fasting Phases — see fat burning, ketosis, and autophagy stages visualized in real time • All Major Fasting Methods — 16:8, 18:6, 20:4, OMAD, 14:10, 12:12, 24h, and custom durations • Streak Tracking with Grace Periods — maintain your momentum even on tough days • Pattern Insights — review your fasting history and discover your most consistent windows • Weight Tracking with BMI — log weight entries and track progress over time • Smart Notifications — reminders that support your schedule, not disrupt it • Beginner-Friendly Onboarding — choose your goal, fasting expertise, and preferred schedule in minutes • 100% Offline — no account, no signup, no cloud required • 15 Languages — English, German, French, Spanish, Polish, Portuguese, Italian, Japanese, Korean, Arabic, Russian, Swedish, Finnish, Norwegian, Turkish UNDERSTAND YOUR FAST, NOT JUST YOUR TIMER Just Fast visualizes the metabolic phases of fasting as they happen: fat burning begins around hour 12, ketosis deepens past hour 18, autophagy activates beyond hour 24. You do not need a biology degree — the app shows you where you are and what your body is doing. FREE AND LIGHTWEIGHT All core features are free. No subscription. No paywall. Just Fast is also one of the lightest full-featured fasting apps available — under 50MB download, compared to 200MB+ for most competitors. Fast to download, fast to start. Note: The app is free with light banner ads on secondary screens (history, settings). The main fasting timer screen is completely ad-free. PERFECT FOR • Beginners starting their first 16:8 protocol • Intermediate fasters exploring 18:6, 20:4, or OMAD • Anyone who wants fasting phases explained without complexity • People managing multiple fasting schedules across 15 languages • Privacy-conscious users who prefer no-account apps Download Just Fast and start your first fast today — no signup required. --- Privacy Policy: https://justfast.app/privacy Support: support@justfast.app
Fastly
This app provides a clean and distraction-free timer for intermittent fasting. It tracks your fasting periods in real-time, offers various popular fasting plans, and automatically monitors fasting phases like fat burning and ketosis. View your history with clear statistics and receive smart reminders.
- Clean fasting timer with real-time tracking
- Multiple intermittent fasting plans
- Automatic fasting phase tracking
- Fasting history with statistics
- Smart reminders for goals
- Minimalist interface
- Dark mode support
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Fastly is a clean, private fasting timer for 16:8, 18:6, OMAD, and custom schedules—without ads, accounts, or distractions. Start a fast with one tap, adjust your start or end time when needed, and see your elapsed time, remaining time, and planned finish at a glance. Fastly keeps the experience focused while giving you the tools you need to understand your routine and track your progress. FOLLOW YOUR FAST See estimated fasting phases based on your elapsed fasting time, including digestion, fat burning, ketosis, and autophagy. Upcoming phase markers make it easy to see what comes next during your fast. TRACK YOUR PROGRESS Review your complete fasting history through clear statistics, charts, and progress insights. Set weight and body fat goals, and optionally connect Apple Health to keep your measurements organized. STAY ON TRACK EVERYWHERE Follow your fasting status from your iPhone, Apple Watch, Home Screen widgets, and complications. Smart reminders help you stay aware of fasting goals and eating windows without unnecessary interruptions. KEY FEATURES • Real-time fasting timer with elapsed and remaining time • Planned fasting end time displayed at a glance • 14:10, 16:8, 18:6, 20:4, OMAD, and custom plans • Estimated fasting phases for digestion, fat burning, ketosis, and autophagy • Upcoming fasting phase markers • Complete fasting history with statistics and charts • Weight and body fat goals with progress benchmarks • Apple Health integration for weight and body fat • Apple Watch app and complications • Home Screen widgets for quick progress checks • Smart fasting and eating-window reminders • Optional private iCloud synchronization • Dark mode and a clean, focused interface PRIVATE BY DESIGN No ads. No third-party analytics. No developer data collection. Your fasting and health information stays on your devices and, when optional synchronization is enabled, in your private iCloud account. IMPORTANT NOTE Fasting phases are estimates based on elapsed time and can vary from person to person. Fastly is intended for general wellness and fasting tracking only. It does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before making medical or dietary decisions.
Screenshots
Verdict
The clearest difference is in-app purchases: Just Fast at none against Fastly's 4. Just Fast also leads on rating (5.0 vs 4.8) and iOS requirement (14.0 vs 17.6). Fastly's advantage is ads (none vs shown) and ratings volume (92 vs 7). On price, review sentiment and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Fastly sells 4 one-off in-app purchases. Just Fast asks for nothing beyond the download.
Just Fast holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Fastly has 92 ratings behind it against 7, so its average is the more settled of the two. Written reviews point the same way: 100% of Just Fast's written reviews are positive against 94% of Fastly's.
Just Fast ships an update every 3 weeks, Fastly every 10 days. The most recent releases landed on September 20, 2026 and September 23, 2026 respectively.
| Parameter | Just Fast | Fastly |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (7 ratings) — better | 4.8 (92 ratings) |
| Positive reviews | 100.0% of reviews — better | 94.1% of reviews |
| Number of ratings | 7 | 92 — better |
| Update frequency | Every 3 weeks | Every 10 days — better |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Monetization | Ad-supported — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod — better | iPhone, Apple Watch |
| Requires iOS | 14.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 47 MB | 9 MB |
| Age rating | 17+ | 12+ |
| Developer | Adrian Cabala | Collweb LLC |
Customer experience
Just Fast
Fastly
In-app purchases
Just Fast
No in-app purchases
Fastly
- Coffee$1.99
- Lunch$4.99
- Become a Supporter$4.99
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- Dinner$9.99









