Dutch cycle app · in development
Your cycle, your prayer and your fasting — in one calm app.
Mensis predicts your period with an honest margin, tracks your hayd status and counts the fasting days you still owe. No trackers, no advertising, and no model will ever be trained on what you log.
Core features free. Forever — and we put that in the terms.
App Store and Google Play — at launch
Cycle day
24
Luteal phase
Four things you can check yourself
Not because they sound good, but because you can read them back in our sub-processor list and our terms.
Whole chain in Europe
Database in Frankfurt. The AI assistant runs on a European inference profile, not in the United States.
See the sub-processorsTrackers and ad SDKs
No attribution SDK, no ad network, no social pixels. Not on this website either.
What we do processModels trained on your data
We train nothing on your data and no supplier is allowed to either. Written into contracts, not assumed.
How we enforce itSignatures needed for access
If anyone here needs to reach user data, it takes two-person approval and a log entry we cannot delete.
Our break-glass procedure
The basics
Predictions that are honest about what they don't know
Most apps hand you a single date and act like it's settled. Mensis works from your last six cycles and shows the uncertainty that comes with them. Logged only one cycle so far? Then the window is wide — and we say so.
Everything about the appAugust 2026
A calendar with shape as well as colour
Your period is a filled dot, your fertile window an open ring, ovulation a droplet. Colour-blind or not, the calendar still reads.
Logging in three taps
One bottom sheet, nine categories, every tap saves immediately. No save button, no form, no waiting.
Contraception mode
Pill, hormonal or copper IUD: your predictions and reminders adjust. On the pill you get your break week instead of an ovulation prediction.
Late is not an error
If your period doesn't arrive, Mensis simply says so: “your period is 3 days later than predicted.” No wrong day 1 shifting your entire cycle.
What no competitor has
Hayd, ghusl and qadaa — built in, not bolted on
For Muslim women the cycle isn't only a health question but a question about prayer and fasting. Mensis ties your hayd status to what you actually logged — never to a prediction — and counts the fasting days you still have to make up.
- Fiqh thresholds you set yourself: habitual duration, maximum hayd duration (10 or 15 days) and minimum tuhr.
- A ghusl reminder only when you log the end of your period. Never on a predicted day.
- A qadaa counter per hijri year, with your confirmation of the Ramadan dates — because mosques differ.
- Discreet mode: a neutral app icon, masked notifications and a privacy screen in the app switcher.
Reviewed for content before we built it
The decision logic, every piece of copy, the counting rules for qadaa and the trigger for the ghusl reminder all go past a fiqh-qualified reviewer before they reach the app. Mensis is a tool, not a fatwa — when in doubt, consult a scholar.
Where this usually goes wrong
What we don't promise
Every app in this category shouts that your data is safe. We'd rather tell you exactly where the limit sits, so you can decide for yourself whether that's enough.
“End-to-end encrypted”
We don't say that. Your data sits readable in our database in Frankfurt. Encrypted in transit and at rest, yes — but that's what every database does and it doesn't protect you from us.
“We can't read along”
Technically we can. So we handle it with procedure instead of mathematics: two-person approval, a recorded reason, and logging that the person granted access cannot remove.
“Fully European”
The data sits physically in Frankfurt, but some of our suppliers are American companies. That means something under the CLOUD Act. We name it ourselves and describe the way out we keep on the table.
“Medically reliable”
Mensis is not a medical device and is not suitable as contraception. A prediction is an estimate based on your own history, nothing more.
Design
No pink. No flowers. No noise.
Two fully-built themes from day one, colours checked against WCAG AA, and a home screen where you can switch off every card. The phase colours below are the same ones in the app — including the contrast values a test in our pipeline guards.
- PeriodFilled dot
- FollicularRing segment
- Fertile windowOpen ring
- OvulationDroplet
- LutealRing segment
Every phase has its own shape as well as its own colour. Colour alone is not information (WCAG 1.4.1).
Price
The core is free and stays free
Logging, predictions, the calendar, insights and the entire deen module cost nothing. That's not an introductory offer: a feature that was ever free never becomes paid here. That rule lives in our terms, not just on this page.
Mensis
Freeforever
- Log your period, flow and nine symptom categories
- Predictions with a visible margin of uncertainty
- Calendar, cycle phases and insights
- The full deen module: hayd, ghusl, qadaa
- Contraception mode and app lock
- Export and full deletion, without emailing anyone
Mensis Plus
Later this year€34.99per year, or €3.49 per month
- Partner mode with a read-only sharing code
- PDF report for your doctor
- Basal body temperature
- Extended pattern analysis
- AI assistant on your own data
Not for sale yet. We don't sell anything before it exists, and there is no paywall in the app at launch.
- Only through the App Store and Google Play — no website subscriptions
- Cancel in two taps, price and term always visible before any trial
- Never advertising, never selling data
Frequently asked questions
All questionsIs my data end-to-end encrypted?
No, and we'd rather say that out loud. Your data sits readable in our database in Frankfurt. It's encrypted in transit (TLS 1.2 or higher) and at rest (AES-256), but that's what any professional database does and it doesn't protect you from us as the provider. What does protect you there is our break-glass procedure: two-person approval, a recorded reason and logging that cannot be erased.
Can you read my notes and deen data?
Technically yes. In practice only through that break-glass procedure, and then with a trail that stays. We think it matters more that you know this than that it sounds good.
Do you sell data or show advertising?
No. Neither, ever. That's a hard commitment in our terms, not only on this page. There is no ad SDK, no attribution SDK and no analytics SDK in the app.
What happens when I delete my account?
Your logs, profile, deen data and conversations are deleted, you're signed out and your local copy is wiped. Live data is gone within 30 days, backups within another 14. Note: your subscription does not stop automatically — you cancel that in your App Store or Google Play settings. The deletion screen in the app says so itself and links you there.
App Store and Google Play — at launch
Mensis is not a medical device and not contraception. Predictions are estimates. Mensis does not issue fatwas. Read more