Splash vs Stardust
Stardust is a playful period tracker with moon and astrology content and optional paid extras. Here is a side-by-side look at both, from each app’s own pages.
In short: Stardust and Splash are both playful, design-led period trackers. Stardust leans on moon phases and astrology and has an optional paid subscription. Splash uses an ocean theme, is free with no paid tier and needs no account. Mozilla’s July 2026 review found Stardust sent some health data to an analytics company; Stardust says that company is contractually restricted.
Last reviewed against Stardust’s own pages · 5 sources · what changed
Both are cute. Stardust leans into moon and astrology content; Splash leans into an ocean world, no account and published detail on how your data is protected.
- Splash
- Free, with no paid tier
- Stardust
- Free to download; optional paid subscription
Choose Splash if
- You want everything free with no subscription
- You want to see exactly what the server can and cannot see
- You prefer cycle science to astrology
Choose Stardust if
- You enjoy moon-phase and astrology content alongside your cycle
- You want a native app
Try it beside Stardust. Splash opens in your browser with no sign-up, and you can import your history and keep both while you decide.
Get Splash, freeSide by side
| Feature | Splash | Stardust |
|---|---|---|
| PriceSource [1] | Free, no paid tier | Free + optional subscription |
| Account neededNot verified for Stardust | No | – |
| Published data-protection detailSource [1] | Server-sees list, AES-GCM-256 | “Your data is private, period.” |
| Independent privacy reviewSource [2] [3] | Not yet reviewed | Mozilla review, July 2026 |
| Native app store appsSource [1] | Android app and web app, with iPhone and Apple Watch apps | iOS and Android |
Where Stardust is stronger
- Moon and astrology content, if that is something you enjoy.[1]
- Native apps from the app stores.[1]
- A large, established user community. Splash is new.
Public record
We include this because privacy is the main reason people compare trackers. It is a dated summary of public sources, not a judgement about Stardust today.
- In June 2022 TechCrunch reported that Stardust shared users’ phone numbers with an analytics company.[4]
- In July 2026 Mozilla tested six period trackers and TechCrunch reported that Stardust was the only one that shared sensitive health data (birthdate, birth control type, reproductive goals and symptoms, linked to a unique identifier) with another company, the analytics firm RudderStack. A Stardust spokesperson said RudderStack is contractually prohibited from selling or using the data for its own purposes.[3][5]
Questions people ask about Splash and Stardust
Is Splash like Stardust?
Both are playful. Splash uses an ocean world and a baby shark instead of astrology, and is free with no account. Stardust offers moon and astrology content and an optional subscription. They suit different tastes, so trying both is easy: Splash opens in your browser with no sign-up.
What did Mozilla find about Stardust?
TechCrunch reported on 16 July 2026 that Mozilla found Stardust sent sensitive health data, linked to a unique identifier, to the analytics company RudderStack, the only one of six trackers tested to share such data. Stardust said RudderStack is contractually prohibited from selling or using it. Read both accounts and decide for yourself.
Can I import Stardust data into Splash?
Splash does not list a Stardust export, so the quickest route is its “Type my last few periods” option, which takes a minute. If you have a spreadsheet of dates from any app, Splash can read that on your phone too. Nothing is uploaded to us.
What changed at the last review
- : Added Mozilla’s July 2026 review of Stardust as reported by TechCrunch, with Stardust’s response. This replaces the earlier note that the review could not be confirmed.
Sources
- Stardust (official site) accessed 2026-10-26
- Mozilla Foundation: Stardust privacy review accessed 2026-10-26
- TechCrunch: Period tracker Stardust shares users’ health data with analytics firm, says Mozilla research (16 Jul 2026) accessed 2026-10-28
- TechCrunch: Stardust shared phone numbers with an analytics firm (Jun 2022) accessed 2026-10-26
- DH Insights: Mozilla report reveals wide privacy gaps among popular period tracking apps (30 Jul 2026) accessed 2026-10-28
Splash facts come from the app itself: local-first storage, optional AES-GCM-256 end-to-end encrypted sync, and imports from Flo, Clue, Apple Health and drip exports.
More comparisons
Try Splash alongside what you use now
Free, no account. Import your history and keep both until you decide.
