# Rhythm SYNC. vs Heartool

The clearest difference is rating: Heartool at 3.1 against Rhythm SYNC.'s 1.8. Heartool also leads on review sentiment (21% vs 13%). Rhythm SYNC.'s advantage is ratings volume (128 vs 14). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Heartool holds the better App Store score, 3.1 against 1.8. That said, the two scores are not equally well evidenced: Rhythm SYNC. has 128 ratings behind it against 14, so its average is the more settled of the two. Written reviews point the same way: 13% of Rhythm SYNC.'s written reviews are positive against 21% of Heartool's.

Rhythm SYNC. ships an update every 3 months, Heartool every 4 months. The most recent releases landed on September 3, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | Rhythm SYNC. | Heartool |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.8 (128 ratings)](https://appshunter.io/ios/app/rhythm-sync/id1226606963/reviews) | **[3.1 (14 ratings)](https://appshunter.io/ios/app/heartool/id1567361608/reviews)** |
| Number of ratings | **128** | 14 |
| Positive reviews | 13.1% of reviews | **21.2% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 4 months |
| Monetization | Free | Free |
| Size | 47 MB | 24 MB |
| Requires iOS | 12.0 | 12.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Scosche](https://appshunter.io/developer/340018842) | [Shenzhen Onecoder Technology Co., Ltd.](https://appshunter.io/developer/1131107345) |

## What reviewers say

### Rhythm SYNC.

[App page](https://appshunter.io/ios/app/rhythm-sync/id1226606963)

This app connects to heart rate monitors to display real-time data, manage activity modes, and track workout history. It allows for software updates and integrates with HealthKit for saving workout data.

**Highlights:** Connects to Rhythm 24 and Rhythm+ monitors, Manages activity modes and biometrics, Displays heart rate and battery level, Configures data sharing with other apps, Collects and downloads recorded activities, Performs software and firmware updates, HealthKit integration

**In-app purchases:** none

**What reviewers like**

- ✅ Accurate heart rate readings
- 🔋 Long-lasting device battery life
- 🔄 Reliable device hardware
- 📱 Simple and straightforward interface
- 🔗 Works well with third-party apps (Peloton, Garmin, Apple Watch)

**What reviewers complain about**

- 🐛 Frequent Bluetooth connection failures
- 🐛 App crashes and freezes regularly
- ❌ App doesn't recognize connected devices
- ⚠️ HRV mode difficult or impossible to access
- 📊 Extremely limited app functionality

**Reported bugs**

- App fails to detect device despite Bluetooth connection
- Bluetooth connection drops frequently during workouts
- App crashes on startup (splash screen freeze)
- Firmware update fails repeatedly
- HRV readings not displaying or accessible

**Requested features**

- HRV (Heart Rate Variability) mode that actually works
- Comprehensive workout history and logging
- Data export to multiple health apps (MyFitnessPal, TrainingPeaks, etc.)
- Customizable heart rate zones that persist
- Batch download and export of multiple files


### Heartool

[App page](https://appshunter.io/ios/app/heartool/id1567361608)

Transform your phone into a fitness tracker to monitor workouts with live heart rate data. Analyze training progress with professional charts and gain insights into your health and cardio condition. Integrates with wearable devices and Apple Health.

**Highlights:** Live heart rate tracking, HRV biofeedback, Cardio health analysis, Workout progress charts, Calorie burned tracking, Health data synchronization

**In-app purchases:** none


## Frequently asked questions

### Is Rhythm SYNC. free?

Rhythm SYNC. is free to download, with no in-app purchases.

### Is Heartool free?

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

### Which has better reviews, Rhythm SYNC. or Heartool?

Heartool is rated higher. Rhythm SYNC. averages 1.8 out of 5 from 128 ratings, while Heartool averages 3.1 from 14 ratings.

### Do Rhythm SYNC. or Heartool have ads?

Neither Rhythm SYNC. nor Heartool shows ads.

### Which is updated more often, Rhythm SYNC. or Heartool?

Rhythm SYNC. ships an update every 3 months, and Heartool every 4 months. Most recently, Rhythm SYNC. was updated on September 3, 2026 and Heartool on September 18, 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.*