# Sonde One vs HeartMath

The clearest difference is rating: HeartMath at 4.9 against Sonde One's 2.9. HeartMath also leads on ratings volume (4.7K vs 45) and review sentiment (74% vs 58%). Sonde One's advantage is in-app purchases (none vs 5) and iOS requirement (13.0 vs 26.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. HeartMath sells 4 in-app purchases, starting at $39.00 per year. Sonde One asks for nothing beyond the download.

HeartMath holds the better App Store score, 4.9 against 2.9. That said, the two scores are not equally well evidenced: HeartMath has 4.7K ratings behind it against 45, so its average is the more settled of the two. Written reviews point the same way: 58% of Sonde One's written reviews are positive against 74% of HeartMath's.

Sonde One ships an update every 6 weeks, HeartMath every 3 weeks. The most recent releases landed on October 11, 2026 and October 21, 2026 respectively.

## The numbers

| Metric | Sonde One | HeartMath |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [2.9 (45 ratings)](https://appshunter.io/ios/app/sonde-one/id1147192738/reviews) | **[4.9 (4.7K ratings)](https://appshunter.io/ios/app/heartmath/id6446414998/reviews)** |
| Number of ratings | 45 | **4.7K** |
| Positive reviews | 58.3% of reviews | **73.8% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Every 3 weeks** |
| Monetization | **Free** | Freemium |
| Size | 69 MB | 185 MB |
| Requires iOS | **13.0** | 26.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 17+ | 4+ |
| Developer | [Sonde Health](https://appshunter.io/developer/1093148075) | [HeartMath Inc.](https://appshunter.io/developer/482739914) |

## What reviewers say

### Sonde One

[App page](https://appshunter.io/ios/app/sonde-one/id1147192738)

This app uses voice analysis to track health conditions by identifying subtle vocal changes. It offers health scores and symptom assessments for enterprise and research users, contributing to groundbreaking voice biomarker research.

**Highlights:** Vocal biomarker analysis, Health condition tracking, Symptom assessments, Enterprise health tool, Voice research participation, Health scores

**Features:** macOS Compatibility

**In-app purchases:** none


### HeartMath

[App page](https://appshunter.io/ios/app/heartmath/id6446414998)

This app helps you manage stress, improve focus, and achieve optimal performance by aligning your heart, mind, and emotions. It offers guided sessions, immersive journeys, and coherence practices based on over 30 years of research.

**Highlights:** Real-time HRV Coherence Measurement, Coherence Training, Scientifically Validated Techniques, Guided Learning Sessions, Progress Tracking, Heart-Brain Coherence Benefits

**Features:** Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| HeartMath Premium | $39.00 | per year |
| HeartMath Premium | $59.00 | per year |
| HeartMath Premium | $79.00 | per year |
| HeartMath Premium | $99.99 | per year |

**What reviewers like**

- 🚀 Huge improvement over previous app
- 👍 Easy to use and highly recommended
- 💡 Loaded with HeartMath techniques and courses
- 👍 Powerful tool for nervous system balance and anxiety reduction
- 👍 Helps achieve a better mental state

**What reviewers complain about**

- 🐛 Connectivity issues with sensor
- 🐛 Sensor not compatible with older devices
- 🐛 App crashes and freezes on newer devices
- 🐛 Inaccurate heart rate and coherence readings
- 🐛 Disruptive screen sleep behavior during sessions

**Reported bugs**

- Sensor connection issues on newer devices
- App crashes and freezes on iPhone 16 Pro
- Inaccurate heart rate and coherence readings
- Screen sleep behavior disrupting sessions

**Requested features**

- Add dark mode option
- Allow playing music/sounds during sessions
- Provide audio feedback on coherence levels
- Add session history customization and details
- Improve sensor compatibility with older devices


## Frequently asked questions

### Is Sonde One free?

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

### Is HeartMath free?

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

### Which has better reviews, Sonde One or HeartMath?

HeartMath is rated higher. Sonde One averages 2.9 out of 5 from 45 ratings, while HeartMath averages 4.9 from 4.7K ratings.

### Do Sonde One or HeartMath have ads?

Neither Sonde One nor HeartMath shows ads.

### Which is updated more often, Sonde One or HeartMath?

Sonde One ships an update every 6 weeks, and HeartMath every 3 weeks. Most recently, Sonde One was updated on October 11, 2026 and HeartMath on October 21, 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.*