Vessel vs JustFast
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Vessel
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Vessel is the smartest way to track your daily hydration. Unlike other apps that count every drink equally, Vessel uses real peer-reviewed research to show you how hydrating your drinks actually are. WHY VESSEL IS DIFFERENT • Scientific hydration multipliers — coffee counts as 92% hydrating (Killer et al. 2014), beer at -10%, spirits at -50% • Beautiful ocean-depth progress ring that deepens as you drink more • Built-in health warnings for excess caffeine, alcohol, and overhydration FEATURES • Fast logging — one tap to add water, coffee, tea, beer, wine, and more • Daily progress ring with smooth water wave animation • Celebration when you hit your goal • 12 achievement badges for streaks and milestones • Week / Month / 3-Month charts with color-coded drink breakdown • Hydration Science page with cited research • Smart reminders at your chosen hours • Apple Health sync for water and caffeine • Body weight-based goal calculator • Dark mode support • Ounces, milliliters, and liters HEALTH WARNINGS Vessel alerts you when: • Caffeine exceeds FDA's 400mg/day limit • Alcohol intake crosses CDC moderate drinking guidelines • Water intake approaches levels that risk hyponatremia (over 3.5L/day) YOUR DATA, PRIVATE All drink data stays on your device. Optional Apple Health sync is fully under your control. No accounts, no tracking, no ads. Drink smarter, not just more.
JustFast
This app offers a straightforward intermittent fasting timer. It focuses on tracking your fast with a clear, calm interface, providing insights into metabolic stages without gamification or pressure. It prioritizes privacy with on-device data storage and no accounts.
- One-tap start and stop
- Live timer with accurate timekeeping
- Metabolic milestone tracking
- Plain-language explanations of milestones
- Adjustable start/stop times
- Ongoing notification for duration
- Simple history of past fasts
- 18 languages and dark design
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Fasting is a beautifully simple intermittent-fasting timer that does one thing well: it tracks your fast. No goals to hit. No streaks to protect. No accounts, no ads, no clutter. Just tap once to begin, and a calm live timer counts your fast while a glowing ring fills toward the next stage your body moves through. WHY IT'S DIFFERENT Most fasting apps pile on dashboards, reminders, and pressure. This one strips fasting back to its essence — a clear timer you can glance at and put away. It's designed to feel quiet and focused, not gamified. WHAT YOU GET • One-tap start and stop, with a big, satisfying button • A live timer that keeps perfect time across restarts, time-zone changes, and daylight saving • Metabolic milestones — the ring fills toward the next stage (blood sugar settling, glycogen burning, fat burning, ketosis, autophagy, and more) • Tap any milestone for an honest, plain-language explanation of what's happening in your body • Forgot to start the timer? Just tap the ring to fix your start time. Forgot to stop? End your fast at the right time after the fact. • An ongoing notification shows your current duration at a glance • A simple history of past fasts — swipe to delete • 18 languages and a clean dark design HONEST BY DESIGN The milestone descriptions are written plainly and honestly. Where the science is still early or based mostly on animal research, we say so. This app is a timer and an educational companion — not medical advice. PRIVATE BY DEFAULT Your data stays on your device. There are no accounts, no sign-ups, no tracking, and nothing is uploaded. Fasting works for 16:8, OMAD, alternate-day, extended fasts, or any schedule you like — because it never forces a schedule on you. Note: Fasting is not a medical device and does not provide medical advice. Talk to a healthcare professional before starting any fasting regimen, especially if you are pregnant, nursing, taking medication, or have a medical condition.
Screenshots
Verdict
The clearest difference is in-app purchases: JustFast at none against Vessel's 3. Vessel's advantage is update cadence (every 4 days vs fortnightly). On price, ads, device support and iOS requirement 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. Vessel sells 3 in-app purchases, starting at $2.99 per month. JustFast asks for nothing beyond the download.
Vessel ships an update every 4 days, JustFast fortnightly. The most recent releases landed on September 14, 2026 and September 28, 2026 respectively.
| Parameter | Vessel | JustFast |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Number of ratings | — | 1 — better |
| Update frequency | Every 4 days — better | Fortnightly |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | — | Free |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 18.0 | 18.0 |
| Further details — not scored | ||
| Size | 5 MB | 20 MB |
| Age rating | 12+ | 4+ |
| Developer | DUMITRU BUMBU | Vitalii Vyrodov |
In-app purchases
Vessel
- Monthly$2.991 Month
- Annual (25% Off)$14.991 Year
- Annual7 Days trial$19.991 Year
JustFast
No in-app purchases





