Simply Fast vs zZz
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Simply Fast
This minimalist app helps you achieve time-restricted fasting goals with a simple, intuitive interface. Configure fasting start times and durations, and receive timely notifications for your fasting and eating windows. No account or sign-in is required.
- Simple and easy-to-use design
- Customizable fasting start times
- Adjustable fasting durations (12-23 hours)
- Fasting and eating window notifications
- No sign-in or account required
- Privacy-focused, no data collection
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Simply Fast is a beautifully simple, no-frills companion for time-restricted eating. Rebuilt from the ground up for the latest iPhone and Apple Watch, it keeps the same clean, one-glance design while feeling right at home on today's devices. Set your window, glance at your progress, and get on with your day. [Features] • Clean, distraction-free design for iPhone and Apple Watch. • Set your fasting start time to any half hour of the day. • Choose a fasting duration from 12 to 23 hours. • A live progress bar shows your current fasting or eating window, with the time remaining at a glance. • Apple Watch complications for modern watch faces, so your window is always one look away. • A notification at the start of each fasting and eating window. • Your schedule stays in sync across iPhone and Apple Watch. • No sign-in, no account, no ads, and no pop-ups. • Private by design: the app collects nothing and sends us no information. [Important] You should consult your doctor before starting or changing a fasting schedule. Simply Fast supports time-restricted eating only, not full-day fasting such as 5:2, and it does not track or store a history of your fasts. [Feedback] We would love to hear from you. Please reach us through the app support page (https://www.mpathy.tech/contact-us). If you find Simply Fast useful, please tell a friend and leave a rating on the App Store. Your support keeps the app going.
zZz
Easily log your sleep with a single tap using home or lock screen widgets. Track time in bed, awake time, and actual sleep duration, syncing data with Apple Health for insightful analysis.
- One-tap sleep logging
- Home and lock screen widgets
- Tracks time in bed, awake, and sleep
- Syncs with Apple Health
- Siri and Shortcuts integration
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One Tap and your sleep schedule is tracked. Add a small widget to your home or lock screen, tap it before going to bed and after waking up and your sleep is tracked. It doesn't get any easier than this. Widgets: • Go to bed • I just woke up • Used to track your sleep as easy as possible Shortcuts & Siri: • Go to bed • I just woke up • Used to track your sleep as easy as possible via Siri, Shortcuts or Automations • Activate in the zZz settings Your time in bed, time awake (the duration before you fall asleep) and your actual sleeping time is saved to Apple Health. The same data is also read from Apple Health to give you great insights into your sleeping schedules.
Screenshots
Verdict
The clearest difference is review sentiment: Simply Fast at 100% against zZz's 0%. Simply Fast also leads on rating (4.5 vs 2.9) and in-app purchases (none vs 1). zZz's advantage is price (Free vs $0.99) and update cadence (every 4 days vs every 2 months). On ads 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
zZz is free to download; Simply Fast costs $0.99 up front. zZz sells 1 one-off in-app purchase. Simply Fast asks for nothing beyond the download.
Simply Fast holds the better App Store score, 4.5 against 2.9. That said, the two scores are not equally well evidenced: zZz has 11 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 100% of Simply Fast's written reviews are positive against 0% of zZz's.
Simply Fast ships an update every 2 months, zZz every 4 days. The most recent releases landed on October 9, 2026 and October 24, 2026 respectively.
| Parameter | Simply Fast | zZz |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 4.5 (2 ratings) — better | 2.9 (11 ratings) |
| Positive reviews | 100.0% of reviews — better | 0.0% of reviews |
| Number of ratings | 2 | 11 — better |
| Update frequency | Every 2 months | Every 4 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Free with in-app purchases — better |
| Devices | iPhone, Apple Watch | iPhone, iPad |
| Requires iOS | 18.0 | 16.0 — better |
| Further details — not scored | ||
| Size | 2 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Mpathy Tech | Florian Schweizer |
Customer experience
Simply Fast
zZz
In-app purchases
Simply Fast
No in-app purchases
zZz
- Pro Tier$0.99
