Comparison

RhythmX vs AsterKit

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

Head to head
About

RhythmX

This app helps you understand your menstrual cycle with a focus on privacy and simplicity. It offers insights into your cycle phases, custom tracking, and educational content without collecting your personal data. All data is stored on your device, and the app is open source.

Highlights
  • Cycle phase insights
  • Customizable symptom tracking
  • Phase calendar view
  • Educational phase information
  • On-device data storage
  • Open source code
  • Optional period reminders
Features
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RhythmX: Your Cycle, Your Rules Take control of your cycle with RhythmX, the menstrual tracker for people who value privacy and simplicity. Built by female engineers who know your body's data is yours, it gives you what you need to understand your cycle without the invasive data collection found in other trackers. Learn each phase in a straightforward way, with no fluff and no gimmicks. Whether you're tracking symptoms, moods, or ovulation, RhythmX helps you build a log that works for you. FEATURES THAT PUT YOU IN CONTROL • Insights: See your current phase at a glance, your average cycle and period length, and an estimate of your next period. Charts show phase timing, your tags, and cervical mucus patterns over time. • Phase Calendar: A month view tinted by phase, with a Today card and predicted period days. Tap any day to add or review tags and notes. • Custom Tags: Track what matters to you. Log symptoms, moods, energy, cravings, exercise, medication, and more, by phase, and edit or remove them any time. • Learn About Your Phases: Understand the science behind the menstrual, follicular, ovulation, and luteal phases, in plain language. • Past Cycles: Archive finished cycles, search your tags, and spot patterns or reflect on how far you've come. • Reminders: Optional notifications the day before and the day of your next predicted period. They are scheduled on your device and need no account. • Share on Your Terms: Export selected phases as a calendar (.ics) file, only when you choose to. • Light and Dark Mode: A calm blush palette in light, deep plum in dark, with a moon icon for each phase. • Accessible by Design: Dynamic Type up to accessibility sizes, VoiceOver labels, and Reduce Motion support. NO DATA COLLECTION, NO COMPROMISES Other apps profit from your most personal information. RhythmX collects nothing. What you log stays on your device. No account, no ads, no analytics, no tracking, and no network access. OPEN SOURCE RhythmX is open source. Contribute to its growth, or read the code to verify how your data is handled. Transparency is not optional. FOR WOMEN, BY WOMEN Designed by a team of female engineers who know what a menstrual tracker should do: protect your privacy, stay simple, and put you in charge. IMPORTANT RhythmX requires iOS 26 or later. Predictions are estimates based on your logged cycles. RhythmX is a tracking tool, not medical advice. Talk to a healthcare professional about health concerns. Because your cycle isn't just data. It's your life. IMPORTANT RhythmX requires iOS 26 or later. Predictions are estimates based on your logged cycles. RhythmX is a tracking tool, not medical advice. Talk to a healthcare professional about health concerns. LEGAL Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://shapehaveninnovations.com/privacy.html

About

AsterKit

Features
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FIRST PERIOD GUIDE New to periods? Open the Guide tab from Calendar or Settings. Plain language, no jargon. Written for anyone at the beginning. AsterKit is a personal wellness app for tracking your cycle. Not a medical device. A private place to log your period and understand your own patterns. THE DIFFERENCE Most period apps track every tap, bundle analytics SDKs, and sell your cycle data to advertisers. AsterKit does none of that. Cycle data stays on your device, protected by the operating system. We have no servers, no database, no copy of your history. HOW IT WORKS A parent completes a quick math check (about 10 seconds) to get started. No PIN, no account. Then the 7-day free trial starts. After day 7, a one-time $4.99 purchase unlocks everything. No subscription, no recurring charges. WHAT YOU CAN DO LOG YOUR PERIOD Record start and end dates. Add intensity (light, medium, heavy, spotting), symptoms, and mood. All stored locally on your device. GENTLE PREDICTIONS After 3+ cycles, see an estimated date for your next period. Based on your personal history. Predictions are estimates only; everyone's cycle is different. ADVANCED INSIGHTS (Premium) Average cycle length, period duration, and consistency patterns. Export a PDF summary to bring to a doctor's appointment. PRIVACY, PLAINLY • Cycle data stays on your device. • We have no servers, no copy of your history. • The only thing that ever leaves your phone: an anonymous receipt token (it confirms your purchase is valid). That's it. • No analytics. No ads. No data sharing. ONE PRICE. YOURS TO KEEP. 7-day free trial, then one-time $4.99. No subscription, no recurring charges, no surprise bills. NOT MEDICAL ADVICE: AsterKit is not a medical device and should not replace professional medical advice. For medical questions about your cycle, consult a healthcare provider. Privacy policy: asterkit.app/privacy Terms: asterkit.app/terms Support: support@asterkit.app (response within 24 hours)

Screenshots

RhythmX4 screens
AsterKit4 screens

Verdict

The call

The clearest difference is device support: AsterKit at 3 against RhythmX's 1. AsterKit also leads on iOS requirement (15.1 vs 26.0). On price, update cadence, ads and in-app purchases 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. RhythmX sells 2 in-app purchases, starting at $1.99 per month and AsterKit sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

RhythmX ships an update fortnightly, AsterKit every 2 weeks. The most recent releases landed on November 4, 2026 and November 5, 2026 respectively.

Scorecard2 real differences · 7 level
RhythmX versus AsterKit: the parameters behind the verdict, then further details
ParameterRhythmXAsterKit
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyFortnightlyEvery 2 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree—
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS26.015.1 — better
Further details — not scored
Size7 MB43 MB
Age rating12+12+
DeveloperShapeHaven Innovations LLCRyan Gonzalez

In-app purchases

2 purchases

RhythmX

Subscriptions1
  • RhythmX Plus Monthly$1.991 Month
One-time1
  • PDF Day Pass$0.99
1 purchases

AsterKit

One-time1
  • AsterKit Premium$4.99

Questions

Is RhythmX free?
RhythmX is free to download, with in-app purchases available.
Is AsterKit free?
AsterKit is free to download, with in-app purchases available.
Do RhythmX or AsterKit have ads?
Neither RhythmX nor AsterKit shows ads.
Which is updated more often, RhythmX or AsterKit?
RhythmX ships an update fortnightly, and AsterKit every 2 weeks. Most recently, RhythmX was updated on November 4, 2026 and AsterKit on November 5, 2026.

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