# REM Sleep Tracker vs Hydrate

The clearest difference is in-app purchases: Hydrate at none against REM Sleep Tracker's 2. Hydrate also leads on device support (3 vs 1). On price, update cadence, ads and iOS requirement there is nothing between them.

Both are free to download. REM Sleep Tracker sells 2 in-app purchases, starting at $9.99 per year. Hydrate asks for nothing beyond the download.

REM Sleep Tracker ships an update every 2 weeks, Hydrate weekly. The most recent releases landed on October 24, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | REM Sleep Tracker | Hydrate |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (49 ratings)](https://appshunter.io/ios/app/rem-sleep-tracker/id6446677275/reviews)** | — |
| Number of ratings | **49** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Weekly** |
| Monetization | Freemium | — |
| Size | 25 MB | 52 MB |
| Requires iOS | 16.0 | **15.1** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Nicola Eusebi](https://appshunter.io/developer/737311863) | [Vir Ventures Inc.](https://appshunter.io/developer/1507713579) |

## What reviewers say

### REM Sleep Tracker

[App page](https://appshunter.io/ios/app/rem-sleep-tracker/id6446677275)

This app analyzes Apple Watch sensor data to provide a sleep quality score. It offers detailed insights into sleep stages, heart rate, and weekly trends, helping users understand and improve their rest habits.

**Highlights:** Sleep quality scoring, Detailed sleep stage analysis (light, deep, REM), Heart rate monitoring, Weekly trend tracking, Sleep bank concept for habit analysis, Apple Health integration

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Sleep Score Premium Yearly | $9.99 | per year |
| Sleep Score Premium Yearly | $29.99 | per year |


### Hydrate

[App page](https://appshunter.io/ios/app/hydrate-water-tracker/id6776859275)

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

**In-app purchases:** none


## Frequently asked questions

### Is REM Sleep Tracker free?

REM Sleep Tracker is free to download, with in-app purchases available.

### Is Hydrate free?

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

### Do REM Sleep Tracker or Hydrate have ads?

Neither REM Sleep Tracker nor Hydrate shows ads.

### Which is updated more often, REM Sleep Tracker or Hydrate?

REM Sleep Tracker ships an update every 2 weeks, and Hydrate weekly. Most recently, REM Sleep Tracker was updated on October 24, 2026 and Hydrate on October 6, 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.*