A minimal, offline fertility tracking app.

It features an overview of the current cycle phase, estimateds your fertility and keeps you in control and responsibility of your personal, medical data.


Zyklus is a PWA - a Progressive Web App. Instead of downloading the app from a digital store, you simply browse to the website with your mobile device and add the website to your Homescreen.

How it Works

The app stores all your data locally on the phone. The advantage is that you don't need to be online to use it and your data isn't transmitted to servers run by companies you don't know.

The downside is that if your phone gets lost you will also loose all your data. This means, you should create backups from time to time.

In the settings is a button to export your data. It will be stored as a plain text file, so make sure to store it in a safe location.

The app is available in English and German and supports and array of color schemes.