Comparison

RHRSpark vs Moss

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

Head to head
About

RHRSpark

Visualize your resting heart rate directly on your Apple Watch face with customizable complications. Choose from various styles and time windows to see your heart rate trends at a glance. Understand how your data is calculated with full transparency.

Highlights
  • Resting heart rate on watch face
  • Sparkline, gauge, or corner complications
  • 10 watch face complications
  • 4 time window options (8H, 24H, 7D, 30D)
  • Two distinct data sources
  • Full calculation transparency
Features
Read full description

RHRSpark puts your resting heart rate on your Apple Watch face as a sparkline, a gauge, or a corner complication. WHAT YOU GET • Three free 24-hour complications: a sparkline, a gauge, and a corner • Seven Pro complications across 8-hour, 7-day, and 30-day windows • Recent sedentary heart rate and Apple's daily resting heart rate, each labeled • Calculation notes for every complication in the iPhone gallery TWO SOURCES, SHOWN CLEARLY The 8-hour and 24-hour views use heart-rate samples that HealthKit labels as sedentary. The 7-day and 30-day views use Apple's daily resting heart rate. When there is no recent sedentary sample, the big number shows Apple's latest resting heart rate and says so. Longer gaps stay visible instead of being filled in. BUILT FOR THE WATCH FACE Choose rectangular, circular, or corner complications. A short HR or RHR label tells you which source you are seeing and leaves the sparkline the room. The Apple Watch app works without the iPhone app and keeps a record of your daily values. The iPhone app adds older days whenever you open it. ONE-TIME PRO UNLOCK Download free and use the three 24-hour complications. Unlock all ten with a single one-time purchase. No subscription, account, ads, or telemetry. PAIR IT WITH HRVSPARK HRVSpark gives the same direct view of raw SDNN heart rate variability across useful time windows. HealthKit data stays on your devices and moves only between your iPhone and Apple Watch through Apple frameworks. RHRSpark may request a small configuration file from filamentlabs.io to show current product messages. That request contains no health data. RHRSpark is for informational purposes only. It does not provide medical advice or diagnose, treat, cure, or prevent any medical condition.

About

Moss

Features
Read full description

There's a kind of meditation app that wants to be part of your life. Moss just wants to get out of the way. Pick a duration. Choose an ambient sound, or silence. Begin. Everything else (session log, streaks, mindful minutes) stays quietly on your device, private and unhurried. Now on Apple Watch, too. Start a session right from your wrist, pick your own duration, and it logs back to your phone automatically. After a session, if you want, leave a quick note on how you felt. Entirely optional, and easy to turn off if it's not for you. No guilt if you miss a day. No badge pressure. Just a still place to return to whenever you're ready to breathe. Moss is for people who already know why they want to meditate. It just makes it easier.

Screenshots

RHRSpark4 screens
Moss4 screens

Verdict

The call

The clearest difference is in-app purchases: Moss at none against RHRSpark's 2. RHRSpark's advantage is update cadence (weekly vs monthly). On price, ads, device support 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. RHRSpark sells 2 one-off in-app purchases. Moss asks for nothing beyond the download.

UpkeepUpdate frequency

RHRSpark ships an update weekly, Moss monthly. The most recent releases landed on October 24, 2026 and October 6, 2026 respectively.

Scorecard2 real differences · 7 level
RHRSpark versus Moss: the parameters behind the verdict, then further details
ParameterRHRSparkMoss
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyWeekly — betterMonthly
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, Apple WatchiPhone, iPad, Apple Watch
Requires iOS17.017.0
Further details — not scored
Size6 MB18 MB
Age rating4+4+
DeveloperJoel FarthingQuiet Leaf LLC

In-app purchases

2 purchases

RHRSpark

One-time2
  • RHRSpark Pro$0.99
  • Tip Jar$2.99
None

Moss

No in-app purchases

Questions

Is RHRSpark free?
RHRSpark is free to download, with in-app purchases available.
Is Moss free?
Moss is free to download, with no in-app purchases.
Do RHRSpark or Moss have ads?
Neither RHRSpark nor Moss shows ads.
Which is updated more often, RHRSpark or Moss?
RHRSpark ships an update weekly, and Moss monthly. Most recently, RHRSpark was updated on October 24, 2026 and Moss on October 6, 2026.

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