Comparison

REM Sleep Tracker vs Hydrate

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

REM Sleep Tracker

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
Read full description

Sleep Monitor is the perfect app for people eager to enhance the quality of their nighttime rest. Thanks to an advanced algorithm, Sleep Monitor processes the data gathered by your Apple Watch sensors to provide you with an overall score representing the quality of your sleep. This innovative app offers a detailed analysis of the different sleep stages, monitoring light, deep, and REM sleep cycles, and providing information about your heart rate throughout the night. Additionally, Sleep Monitor allows you to track your progress with the "sleep bank" concept, a repository of your rest data that helps you better understand your habits and identify any issues. With Sleep Monitor, you can also monitor the weekly trends of various parameters, such as sleep duration, rest quality, and time spent in each sleep stage. This valuable information will enable you to make targeted lifestyle changes to improve your nighttime rest. Don't miss the opportunity to transform your Apple Watch into a powerful tool for better sleep and waking up more rejuvenated each day. Sleep Monitor is the ideal app for those seeking an ally in sleep management, with an intuitive design and a rich array of features. Download Sleep Monitor today and begin your journey towards more restful and regenerative sleep. Maximize the potential of your Apple Watch and discover how quality rest can improve your daily life! HealthKit Integrated with Apple Health for sleep stages, heart rate, respiratory frequency, age and gender data to calculate sleep quality. Sleep Monitor Premium Sleep Monitor offers a Premium version available as an auto-renewable subscription. Payment will be charged to iTunes Account at confirmation of purchase. Subscriptions automatically renew unless auto-renew is turned off at least 24-hours before the end of the current period. Account will be charged for renewal within 24-hours prior to the end of the current period at the rate of your selected plan above. Subscriptions may be managed by the user and auto-renewal may be turned off by going to the user's Account Settings on the device. Once purchased, refunds will not be provided for any unused portion of the term. Privacy policy: http://app.sleepscoreapp.com/Home/Privacy Terms of use: http://app.sleepscoreapp.com/Home/Terms

About

Hydrate

Features
Read full description

Hydrate is a calm, beautiful way to build a daily water habit—without clutter, accounts, or ads. Hydrate Better. Feel Better. Set your daily goal once (most adults aim for 2,000–2,500 ml). Log throughout the day and always see how much is left. No spreadsheets, no guilt—just a clear picture of today. Tap once, log a sip 250 ml, 500 ml, and 750 ml quick-add buttons stay one tap away. Save custom vessels for your bottle, mug, or cup so logging matches real life. Haptic feedback confirms every log. Watch your glass fill up A living 3D water glass shows exactly how close you are to your target—animated waves, rising bubbles, and a satisfying splash when you add more. Big typography counts up your intake so you always know where you stand. Celebrate when you hit your goal. Cross your daily target and confetti bursts across the screen. Sparkles shimmer on a full glass. Small wins that keep you coming back. Streaks for days you hit your goal Your streak counts consecutive days you reach your daily target—not just days you opened the app. A compact badge on Home keeps your momentum visible. History that makes sense. Overview shows today's progress ring, a weekly bar chart, your daily average, and best streak. Switch to Calendar to browse a month at a glance, tap any day for a full log with times and amounts, and see which days you crushed your goal. Works offline. Every log saves on your device first, so the app stays fast. No account. No hassle. Anonymous sign-in—no email, no password wall. A short onboarding flow (welcome, name, goal) and you're tracking. No ads. No selling your data. Hydrate is free and ad-free. We don't sell your personal information—see our privacy policy for details. Highlights • Stunning 3D glass with wave animation, bubbles, and splash effects • Hero intake display with animated count-up typography • Goal celebration with confetti and haptics • Quick-add buttons (250 / 500 / 750 ml) + custom vessels • Editable daily goal in Settings • History Overview with weekly chart, average, and best streak • Calendar history with per-day detail • Goal-based streak counter • Local-first storage with optional cloud sync • Warm, minimalist design with refined typography and card surfaces Start small. Stay consistent. Hydrate.

Screenshots

REM Sleep Tracker4 screens
Hydrate3 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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.

UpkeepUpdate frequency

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.

Scorecard2 real differences · 8 level
REM Sleep Tracker versus Hydrate: the parameters behind the verdict, then further details
ParameterREM Sleep TrackerHydrate
PriceFreeFree
Rating4.2 (49 ratings) — better—
Positive reviews0.0% of reviews—
Number of ratings49 — better—
Update frequencyEvery 2 weeksWeekly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemium—
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.015.1 — better
Further details — not scored
Size25 MB52 MB
Age rating4+4+
DeveloperNicola EusebiVir Ventures Inc.

In-app purchases

2 purchases

REM Sleep Tracker

Subscriptions2
  • Sleep Score Premium Yearly$9.991 Year
  • Sleep Score Premium Yearly7 Days trial$29.991 Year
None

Hydrate

No in-app purchases

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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