Caffeine App vs ONYX EMS
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Caffeine App
Track your caffeine intake from various beverages and monitor your hydration levels. Visualize your caffeine curve over 24 hours and receive notifications for your optimal sleep time. Integrates with Apple Health and Apple Watch for seamless logging and data syncing.
- Log caffeine from coffee, tea, and energy drinks
- Visualize 24-hour caffeine curve
- Calculate optimal sleep time
- Track daily water intake
- Apple Watch logging and complications
- Apple Health integration
- iCloud sync
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How much caffeine is still in your body? When can you fall asleep? Are you drinking enough water? Caffeine App gives you the answers — at a glance. Caffeine Tracking • Log every coffee, tea, espresso, energy drink, or mate • Scrollable 24-hour timeline shows your caffeine curve • See how much caffeine is currently in your system • Create custom drinks with individual caffeine amounts • Caffeine calculator for drinks with unusual sizes Optimal Sleep Time • Caffeine App calculates when you're ready to sleep • Get notified when your sleep time is reached • Set your personal caffeine limit and desired sleep time Water Tracking • Track your daily water intake with personalized goals • Save your favorite glass and bottle sizes • Customizable reminders to stay hydrated Statistics • Daily caffeine and water charts across your full history • See which drinks make up most of your caffeine • Compare your water intake against your daily goal Widgets • Caffeine Now: current caffeine level and 30-day history • Water Intake: today's progress towards your goal • Quick Log: log your favorite drink with one tap • Home Screen and Lock Screen widgets Apple Watch • Log caffeine and water right from your wrist • Daily charts for caffeine and water • Complications show your optimal sleep time More Features • Apple Health integration — caffeine and water entries stay in sync • iCloud sync across all your devices • Dynamic Type for optimal readability • URL scheme support
ONYX EMS
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onyx EMS is a fitness software that controls corresponding equipment through Bluetooth, allowing users to select different modes to achieve various fitness goals
Screenshots
Verdict
The clearest difference is in-app purchases: ONYX EMS at none against Caffeine App's 1. ONYX EMS also leads on update cadence (every 6 days vs monthly) and iOS requirement (9.0 vs 18.0). On price, 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
Both are free to download. Caffeine App sells 1 one-off in-app purchase. ONYX EMS asks for nothing beyond the download.
Caffeine App ships an update monthly, ONYX EMS every 6 days. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.
| Parameter | Caffeine App | ONYX EMS |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (341 ratings) — better | — |
| Positive reviews | 73.7% of reviews | — |
| Number of ratings | 341 — better | — |
| Update frequency | Monthly | Every 6 days — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, Apple Watch, Vision Pro — better | iPhone, iPod |
| Requires iOS | 18.0 | 9.0 — better |
| Further details — not scored | ||
| Size | 20 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Oleg Mueller | VOLT BOX LIMITED |
Bugs and requests
Caffeine App
Reported bugs
10 issues- Sleep ready time displays current time instead of predicted sleep time
- Cannot rename custom amounts until after adding them
- Newly added custom amounts appear at bottom of list
- Health app data from third-party apps not syncing
- All presets missing in some versions
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- HealthKit integration broken in certain versions
- Shift work time differential not processed correctly
- Outdated caffeine data for Dunkin Donuts beverages
- Graphics update delays causing app unresponsiveness
- Watch app loading issues on initial launch
Requested features
20 requests- Toggle option to disable bar chart visualization
- Taller graph display area with scrolling capability
- Personalization based on body weight and metabolism
- Ounce-based measurement options for drinks
- Multi-day and historical trend analysis
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- Siri Shortcuts integration for automated logging
- Today widget for quick access
- Mood and energy level tracking
- More granular unit adjustments (fractions of shots)
- Expanded beverage library (Monster Java, Sheetz coffee, K-cups, etc.)
- Custom coffee group creation without preset requirements
- Apple Watch complications showing current caffeine levels
- Watch app graph visualization
- Headache threshold level tracking
- Future-looking graph projections
- Water consumption tracking integration
- Ability to rename custom amounts before adding
- Custom amounts appearing at top of list instead of bottom
- Shift work schedule support
- Average daily caffeine statistics
ONYX EMS
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Caffeine App
- Unlock Pro$4.99
ONYX EMS
No in-app purchases
