Julia Friesel, Marie Kochsiek, Tina Baumann


Drip is a non-commercial period tracking app that implements a scientifically proven method called "sympto-thermal method" for calculating fertility. The app is designed to only function locally, and there are no servers that store any of your data. The app’s code is open-source, which means you can check how the application works and you can modify it to your needs if you like. The app uses a gender neutral design and UI and aims for a neutral and rather encouraging language. This is an important aspect for us because many apps on the market reinforce gender stereotypes.

Our goal is to make fertility and period tracking technology more transparent but also more secure, so that people who menstruate can use technology that serves as a tool to help getting to know their own bodies and health better without worrying about their data being used in ways they are not aware of.

We started the development in 2018 and have grown a community of contributors around it. We run regular meetups where we help new people get started with the project and work together on new features.

The Fellowship will allow us to review user’s feedback of our first beta release version of drip and prepare the first release on F-Droid and eventually on Google Play Store. We will also work on open source community building.

If you want to contribute to Drip or join one of our meetups please get in touch: We’re @Bl00dyHealth on Twitter, the website is or you can write us an email:

Marie is a social scientist and software engineer with an interest in the intersections between technologies and societies, especially with respect to digital health tracking and digital rights. She is a member of the feminist hackspace Heart of Code in Berlin. Her favourite inventions are password managers and menstrual cups.

Tina has a background in mathematics, values privacy and likes to keep up with feminist topics. While learning more about menstruation, ovulation and cycles, she noticed how good it feels to be able to make informed decisions. She found herself wanting a modern tool that she could use to learn more about her body and that which respected her privacy at the same time. With a do-it-yourself mindset and an interest in improving her programming skills, she welcomed the opportunity to create an app with like-minded people.

Julia is a software developer with a background in social sciences. She’s used cycle tracking apps for a really long time and is regularly surprised at the amount of design and privacy issues that cycle tracking app users have to put up with. She thinks it’s important to show that open-source software isn’t limited to operating systems and word processing programs but the technology used by women* everyday as well.