# HRV4Biofeedback vs Diary!?

The clearest difference is price: Diary!? at Free against HRV4Biofeedback's $9.99. Diary!? also leads on update cadence (every 2 days vs every 2 months). HRV4Biofeedback's advantage is in-app purchases (none vs 1) and chart position (#44 vs unranked). On ads, device support and iOS requirement there is nothing between them.

Diary!? is free to download; HRV4Biofeedback costs $9.99 up front. Diary!? sells 1 in-app purchase, starting at $4.99 per month. HRV4Biofeedback asks for nothing beyond the download.

HRV4Biofeedback ships an update every 2 months, Diary!? every 2 days. The most recent releases landed on October 13, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | HRV4Biofeedback | Diary!? |
| --- | --- | --- |
| Price | $9.99 | **Free** |
| Rating | **[3.4 (29 ratings)](https://appshunter.io/ios/app/hrv4biofeedback/id1504638613/reviews)** | — |
| Number of ratings | **29** | — |
| Positive reviews | 53.1% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 days** |
| Monetization | Free | — |
| Best chart rank | **#44** | — |
| Size | 138 MB | 28 MB |
| Requires iOS | 15.6 | 15.6 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [A.S.M.A. B.V.](https://appshunter.io/developer/1066843463) | [The Boggler Inc.](https://appshunter.io/developer/6788566622) |

## What reviewers say

### HRV4Biofeedback

[App page](https://appshunter.io/ios/app/hrv4biofeedback/id1504638613)

**Currently charting:** #44 Top Paid · Lifestyle (US App Store)

This app uses your phone's camera to measure heart rate variability and provide biofeedback. It guides you through deep breathing exercises to improve self-regulation and manage stress. Track your progress and explore correlations with your daily experiences.

**Highlights:** Camera-based HRV measurement, Real-time heart rate feedback, Resonant frequency analysis, Biofeedback score, Subjective annotations, HealthKit integration, Bluetooth sensor support

**Features:** Vision Pro support

**In-app purchases:** none


### Diary!?

[App page](https://appshunter.io/ios/app/diary/id6788566620)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| AI Guide Monthly | $4.99 | per month |


## Frequently asked questions

### Is HRV4Biofeedback free?

HRV4Biofeedback costs $9.99, with no in-app purchases.

### Is Diary!? free?

Diary!? is free to download, with in-app purchases available.

### Do HRV4Biofeedback or Diary!? have ads?

Neither HRV4Biofeedback nor Diary!? shows ads.

### Which is updated more often, HRV4Biofeedback or Diary!??

HRV4Biofeedback ships an update every 2 months, and Diary!? every 2 days. Most recently, HRV4Biofeedback was updated on October 13, 2026 and Diary!? on October 5, 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.*