# Caffeine App vs ONYX EMS

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.

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.

## The numbers

| Metric | Caffeine App | ONYX EMS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (341 ratings)](https://appshunter.io/ios/app/caffeine-app-daily-tracker/id1045959983/reviews)** | — |
| Number of ratings | **341** | — |
| Positive reviews | 73.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Monthly | **Every 6 days** |
| Monetization | Free with in-app purchases | — |
| Size | 20 MB | 6 MB |
| Requires iOS | 18.0 | **9.0** |
| Devices | **iPhone, Apple Watch, Vision Pro** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Oleg Mueller](https://appshunter.io/developer/367875607) | [VOLT BOX LIMITED](https://appshunter.io/developer/1669508356) |

## What reviewers say

### Caffeine App

[App page](https://appshunter.io/ios/app/caffeine-app-daily-tracker/id1045959983)

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.

**Highlights:** 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

**Features:** Apple Watch app

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock Pro | $4.99 | one-time |

**What reviewers like**

- 👍 Easy to use and intuitive interface
- 🎯 Accurate caffeine tracking and decay calculations
- ⏰ Helpful sleep readiness predictions
- 🏥 Apple Health integration for long-term tracking
- ⌚ Apple Watch support with quick logging

**What reviewers complain about**

- ⚠️ Recent performance degradation from new features
- 📊 Graphs become too small with multiple charts enabled
- ⏳ Long graphics update delays affecting responsiveness
- 🐛 Sleep ready time shows current time instead of prediction
- 🌍 Limited beverage library for non-German markets

**Reported bugs**

- 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

**Requested features**

- 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


### ONYX EMS

[App page](https://appshunter.io/ios/app/onyx-ems/id6762114947)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Caffeine App free?

Caffeine App is free to download, with in-app purchases available.

### Is ONYX EMS free?

ONYX EMS is free to download, with no in-app purchases.

### Do Caffeine App or ONYX EMS have ads?

Neither Caffeine App nor ONYX EMS shows ads.

### Which is updated more often, Caffeine App or ONYX EMS?

Caffeine App ships an update monthly, and ONYX EMS every 6 days. Most recently, Caffeine App was updated on October 24, 2026 and ONYX EMS on October 25, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*